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[Display omitted] • Effect of plasma treatment and six different fluxes on solder wetting was studied. • Copper samples treated by N 2 /H 2 plasma exhibited excellent wetting with any flux. • Even expired fluxes can be successfully used for soldering of plasma-treated connectors. • Flux cannot be omitted from soldering due to the remaining thin oxide/organic layer. • Plasma treatment allows much less active flux to be used in the soldering process. To enhance the solderability, highly active fluxes are commonly employed in lead-free soldering. However, there are industry-wide efforts to use less active fluxes to avoid possible issues associated with corrosion processes and minimize subsequent cleaning processes, thereby reducing potential environmentally harmful waste. Therefore, in this study, the effect of the plasma treatment (N 2 /H 2 97:3) on the wettability of the soldered surface (copper connectors) was investigated. Wettability measurements were conducted using SAC305 solder alloy and six different fluxes. The wetting balance test revealed a significant improvement in wetting for all tested fluxes, regardless of their composition. On the other hand, non-wetting occurred when no flux was applied to the plasma-treated surface, attributed to a thin residual oxide layer detected by X-ray photoelectron spectroscopy. Thus, the plasma treatment of the surface supports the flux effect, which cannot be entirely omitted from the soldering process. However, incorporating plasma treatment in the soldering process allows for the use of much less active or even expired fluxes. [ABSTRACT FROM AUTHOR]

[Display omitted] • An organic carboxylic acid depressant was introduced to oxidized mineral flotation. • The depressant gallic acid can effectively separate scheelite from cassiterite. • The selective depression mechanism of cassiterite by gallic acid was revealed. • A model of the selective depression mechanism of gallic acid was constructed. Scheelite and cassiterite are common tungsten and tin oxide minerals that often coexist in nature. However, the similar oxidation degrees and solution and surface chemical properties of scheelite and cassiterite pose challenges to their flotation separation. Moreover, research in this area is currently limited. This study investigated the selective depression mechanism of gallic acid (GA) in the flotation separation of scheelite and cassiterite and successfully achieved the effective separation of the two minerals. Single mineral and artificially mixed mineral experiments were performed to analyze the flotation separation behavior of scheelite and cassiterite. The results revealed that in the absence of a depressant, scheelite and cassiterite exhibited recovery of 93.43 % and 89.72 %, respectively. After the addition of 5 × 10−4 mol/L GA to the mineral slurry, the grades of WO 3 and Sn in the flotation concentrates were 48.93 % and 18.13 %, with recovery of 82.50 % and 31.62 %, respectively. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential, adsorption amount, contact angle, and atomic force microscopy imaging analyses were conducted to examine the selective depression mechanism of GA in the flotation separation of scheelite and cassiterite. In the slurry, the cassiterite surface provided active Sn sites for the chemical adsorption of GA. Moreover, the phenolate O- donor atoms of the deprotonated polar groups of GA will undergo coordination with metal ions and then adsorb on the mineral surface. GA forms metal gallate through adsorption of its –COOH and –OH groups on mineral surface and produces textured oxide layer rich in OH groups, thus reducing the surface hydrophobicity of cassiterite and then depressing cassiterite. The selective adsorption of GA on the cassiterite surface hindered the further adsorption of NaOL, thereby reducing its surface hydrophobicity. Therefore, GA finally realized the flotation separation of the two minerals. [ABSTRACT FROM AUTHOR]

[Display omitted] • PA was introduced as a high-efficiency and environment-friendly galena depressant in chalcopyrite flotation. • PA exhibited stronger adsorptive capacity on galena than on chalcopyrite. • Surface properties of galena were markedly altered following exposure to PA. • Interaction between galena and SBX was attenuated with participation of PA. Novel eco-friendly organic depressants with high selectivity are attracting ever-growing interests. The selective inhibition effect of pyrogallic acid (PA) on galena in chalcopyrite flotation was investigated in this study. Flotation trials showed that PA markedly depressed galena with only a small effect on chalcopyrite, which contributed to the separation of chalcopyrite and galena by flotation after adding a low dosage of PA. Surface hydrophobicity tests suggested that PA strongly adsorbed on galena but not on chalcopyrite, which attenuated the adsorption activity of collector on galena, thus rendering galena highly hydrophilic. Conversely, chalcopyrite still retained favorable floatability. These findings were corroborated by the results obtained from infrared and surface adsorption measurements. Results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy measurements also validated the strong adsorption of PA on galena. This behavior promoted the generation of other hydrophilic species on galena. In addition, molecular dynamic simulations demonstrated that PA tended to adsorb on galena, and water molecules accumulated on galena following PA adsorption, which would decrease the floatability of galena. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoO 3 /MoS 2 /ZnS ternary composites were synthesized using a facile hydrothermal method. • Multiple heterogeneous interfaces of the MoO 3 /MoS 2 /ZnS ternary composites were observed. • The degradation efficiency achieves 97.9 % of MB in 40 min with the MB loading of 20 mg/L using the photocatalyst dosage of 10 mg. • A photocatalytic mechanism of the MoO 3 /MoS 2 /ZnS ternary composites for the photodegradation of MB is schematically illustrated. Engineering the multiple heterojunctions of MoS 2 -based materials provides an important and effective strategy to improve photocatalytic activity. In this work, the insufficiently vulcanized MoO 3 intermediates had been incorporated into MoS 2 /ZnS nanostructured composites using a facile hydrothermal method. The analysis of scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) shows that the multiple heterojunctions were formed among the sphalerite ZnS, molybdenum oxide (MoO 3) and MoS 2 nanocrystals. Different heterogeneous microstructures among nanosheets, nanoparticles and nanobelts were aggregated through changing the mole fraction of the molybdenum in the mixture precursors. Photocatalytic results confirm that the relatively low ratio of Mo+4/Mo+6 in the ternary composites can significantly improve the catalytic activity for efficiently degrading the organic dye due to the synergistic effect of the multiple heterojunctions. The degradation efficiency achieves 97.9 % of methylene blue (20 mg/L) in 40 min using the photocatalyst dosage of 10 mg. A possible photocatalytic mechanism is also proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Systematic studies of the formation of SiC layer on carbon ions-bombarded surface of Si were performed. • Amorphization of carbon substrate at low fluence of ion beam were detected. • Absence of the segregation of carbon impurities were observed for low fluences. • Formation of high-quality 6H-SiC films at highest fluence were detected. • Excessive carbon demonstrate tendency to formation of oxidized disordered nanostructures. Systematic studies of the gradual fabrication by means of carbon ion-implantation of high-quality 6H-SiC layers on silicon surfaces have been carried out. The fluence of carbon ions varied from 5 × 1015 cm−2 to 1017 cm−2. Results of first-principle calculations, X-ray diffraction (XRD), and Raman spectroscopy demonstrate the amorphization of silicon substrate without any tendency to the segregation of carbon in the samples synthesized at low fluencies. The formation of a SiO 2 -like structure at this stage was also detected. X-ray photoelectron spectroscopy (XPS), XRD, and Raman spectroscopy demonstrate that an increase in carbon content at 1017 cm−2 fluence leads to the growth of 6H-SiC films on the surface of the amorphous silicon substrate. Atomic force microscopy (AFM) data obtained also demonstrates the decreasing of surface roughens after the formation of SiC film. XPS and Raman spectra suggest that excessive carbon content leaves the SiC matrix via the formation of an insignificant amount of partially oxidized carbon nanostructures. Optical measurements also support the claim of high-quality 6H-SiC film formation in the samples synthesized at 1017 cm−2 fluence and demonstrate the absence of any detectable contribution of nanostructures formed from excessive carbon on the optical properties of the material under study. [ABSTRACT FROM AUTHOR]

Hard X-ray photoelectron spectroscopy (HAXPES) was used to perform a non-destructive depth profile of AlCrNbYZrN x (x = 0 to ∼ 50 at.%) thin films. The outermost native oxide of the pristine thin films contained the highest coordination oxides of every metal. Substoichiometric oxides or oxynitrides were found underneath. After exposure to 1.0 M HCl, increases in the most highly coordinated oxides of Cr, Nb, and Al in films with up to 37 at.% N were observed, suggesting that the low coordination oxides and oxynitrides in the subsurface had been further oxidised and were intermediary compounds in the passivation process. Al and Y oxides were lost to the HCl electrolyte, in agreement with their respective Pourbaix diagrams. The film with 49 at.% N showed little to no change in the data due to its high porosity which led to the oxide being detected at all probed depths. The metal core level spectra revealed a preferential order in which nitrogen bonded with the different metals. Nitrogen interacted first with Y, then Zr, then Al and Nb, and lastly Cr as the nitrogen content was increased. [Display omitted] • Non-destructing depth profiling of AlCrNbYZrN x passive layers performed by HAXPES. • The outermost native oxide contains highest coordination oxide of every metal. • Sub-oxide contains substoichiometric oxides and oxynitrides. • Increased abundance of Cr, Nb and Al oxides after exposure to 1M HCl. • A preferential nitrogen-metal interaction followed formation enthalpies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Demonstrated utility of open-source x-ray microanalysis software, BadgerFilm, towards thin film applications for first time. • Combination of x-ray microanalysis experiments and data analysis by BadgerFilm yielded reliable composition and thickness data for a suite of metallic glass thin films. • Identified surface oxidation layer's composition and thickness using combination of x-ray photoelectron spectroscopy and x-ray microanalysis. Metallic glass thin films (MGTFs) are a recently developed class of alloy coatings with potential applications ranging from biomedical devices to electrical components. Their tribological performance in service conditions is dictated by MGTF bulk composition but can be limited by the native oxide surface that inevitably forms upon exposure to atmosphere. Surface oxidation, thickness, and composition of ZrCuNiAl MGTFs were characterized using a combination of X-ray photoelectron microscopy (XPS) and electron probe microanalysis (EPMA). MGTF samples with nominal thicknesses of 50, 500, and 1500 nm were sputtered onto Si and SiN wafer substrates within a high vacuum deposition chamber and their amorphicity was confirmed by X-ray diffraction. XPS depth profiling identified the thin film composition and showed that the surface oxide was dominated by a mixed layer of mostly ZrO 2 , a little oxidized Al, and some metallic Zr. EPMA X-ray intensities were acquired as a function of beam energy to excite characteristic X-rays from different depths of the MGTFs and reconstructed using open-source thin film analysis software BadgerFilm , to determine the composition and thickness of sample layers. EPMA results constrain the composition to be Zr 54 Cu 29 Al 10 Ni 7 within 0.7 at. % variation and total thicknesses to be 49, 470, and 1546 nm. Using the oxide composition identified from XPS depth profiling as an input for BadgerFilm analysis, EPMA results indicate the surface oxidation layer on each of the thin film samples was 6.5 ± 1.1 nm thick and uniform across a 0.25 mm region of the film. [ABSTRACT FROM AUTHOR]

[Display omitted] • PNGN was synthesized by hydrothermal approach. • PANI/PNGN 15% composite synthesized by in-situ polymerization method. • The sensor has shown sensing response ∼810 %, detection limit of 0.012 ppm. • Response time and recovery time are 21 s and 56 s. • PANI/PNGN 15% exhibits a remarkable specific capacitance of 750.41 F g−1 at 5 Ag−1. In the pursuit of developing advanced materials with multifunctional capabilities, the integration of polymers and graphene-based materials has garnered significant attention. In the quest for the synergy between polyaniline (PANI) and phosphorus, nitrogen dual co-doped graphene (PNGN) has emerged as a promising avenue for multifunctional applications in supercapacitors and gas sensing devices. The PANI/PNGN 15 % nanocomposites were synthesized by a combination of hydrothermal processing and in-situ polymerization techniques. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. The PANI/PNGN 15 % nanocomposite sensor has shown sensing response values of ∼810 %, the response time of 21 s, recovery time of 56 s, and a detection limit of 0.082 ppm. The PANI/PNGN 15 % nanocomposite achieved a remarkable specific capacitance of 750.41 F g−1 at a current density of 5 A g−1. Moreover, the symmetrical supercapacitor exhibits remarkable rate capability, achieving (∼82.14 % at 5 Ag−1), while also maintaining excellent cycling stability. The synergistic effects of PANI and PNGN contribute to the development of high-performance devices, paving the way for advancements in the fields of supercapacitors and gas sensing technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nano/sub-micron pores, along with topography changes from LSPwC, cues for controlling gene expression and cell adhesion. • Surface oxide is mostly composed of mainly Ti4+ and a small amount of Ti3+ is crucial for tribo-corrosion resistance. • Synergistic porous topography and surface oxide crucial for tribo-corrosion, gene expression, and stem cell conformation. Laser shock peening without coating (LSPwC), a prospective surface modification technique for improving the mechanical aspects of Ti-6Al-4V alloy for automotive/aerospace sector, is also expected to dictate the efficiency of this material class for implant application. Here we unravel the impact of LSPwC on Ti-6Al-4V material surface characteristics, in-vitro tribocorrosion and biocompatibility. Micrography shows the presence of nano and sub-micron sized pores after LSPwC process. The role of nano and sub-micron sized pores along with topography modification induced by LSPwC to serve as cues for controlling gene expressions, cell adhesion and activities offer novel insights in this research direction. A detailed X-ray photoelectron spectroscopy analysis detected local chemical non-stoichiometry with reduced number of oxygen diffusion channels. A crucial outcome of this oxide layer modification is the negative skewness (−0.55 ± 0.11) and reduced kurtosis (3.49 ± 0.14) of the surface, along with localized plastic deformation. These factors are correlated with the shift in potential during fretting tribo-corrosion from −800 to −250 mV after LSPwC, accompanied by a lower coefficient of friction of 0.4. Furthermore, the presence of well-spread cells and the up-regulation of beneficial genetic markers (Ki67) on LSPwC surfaces have the potential to form a better bone-material interface. The findings open new frontiers of the LSPwC-treated Ti-6Al-4V surface to synergistically modulate the tribocorrosion and biocompatibility aspects, with exciting possibilities for biomedical implants. [ABSTRACT FROM AUTHOR]

[Display omitted] • SC-500 exhibited lower triclosan adsorption due to the electrostatic repulsion. • SC-500 exhibited higher triclosan degradation due to higher Fe2+ content to produce more ∙OH. • Aromaticity of dissolved organic matter is positively correlated with the degradation of TCS. When sludge biochar (SC) prepared from sewage sludge was used to remove triclosan (TCS) from both aqueous solution and soil, the adsorption capacity increased with increasing pyrolysis temperature, while the degradation rate showed a different pattern, namely, SC-500 > SC-800 > SC-600 > SC-700. TCS degradation rate achieved nearly 100 % at 2 h with SC-500 used as a Fenton catalyst. Aromaticity of dissolved organic matter (DOM) was positively correlated with the degradation of TCS and adding homologous DOM solution shortened the equilibrium time of TCS degradation, while removing DOM from SC prolonged, compared to the original SC. The results of X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectrometer (EPR) characterization indicated that SC-500 performed a stronger catalytic degradation ability due to the relatively high Fe2+ content to produce more ∙OH and SC-derived DOM act as an electron shuttle to promote other reactive oxidative species generation through two free radical pathways in the activation of H 2 O 2 by Fe2+, which in turn promoted the degradation of TCS. [ABSTRACT FROM AUTHOR]

[Display omitted] • A monolithic 3D Z-scheme photocatalyst was developed for CO 2 to CO conversion. • Bi 2 WO 6 /g-C 3 N 4 /Cu foam shows high CO yield and stability under visible light. • The enhanced CO 2 reduction performance and mechanism were analyzed. • Novel strategy for efficient photocatalytic CO 2 reduction. Photocatalytic CO 2 reduction to hydrocarbon fuels represents a promising solution to CO 2 emission challenges. However, photocatalytic CO 2 reduction systems face hurdles in practical utilization for the low efficiency of photocatalysts and challenge in catalyst immobilization. Therefore, a novel monolithic three-dimensional Z-scheme photocatalyst was synthesized by fabricating Bi 2 WO 6 /g-C 3 N 4 heterojunction on Cu foam substrate (Bi 2 WO 6 /g-C 3 N 4 /Cu foam) via thermal polymerization and electrophoresis deposition. A series of characterization results, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N 2 adsorption–desorption, illustrate the crystalline properties, pore structure, and morphology of the composite photocatalyst. Consequently, Bi 2 WO 6 /g-C 3 N 4 /Cu foam achieved CO production yield of 33.84 μmol/g cat under visible light illumination for 6 h and retained 96.2 % of initial photocatalytic activity after 30 h of reaction. UV–Vis diffuse reflection spectra, photoluminescence spectra and photoelectrochemical analysis was involved to reveal the mechanism of the photocatalytic activity of composite photocatalyst. The synergistic effect of the Z-scheme mechanism and the hierarchical macroporous structure improves the light absorption, light-induced electron-hole pair separation, and charge transmission. This catalyst construction strategy provides a viable approach for facilitating practical photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • PMMA capped ZnO specimens were prepared by ex-situ surface capping process by varying PMMA concentration. • PMMA surface capping suppresses defects like zinc interstitials, and both surface and lattice oxygen vacancies in ZnO. • Band alignment, oxygen vacancies, and FRET between PMMA and ZnO alter absorption and luminescence, affecting band-edge and emission intensities. • PMMA-capped ZnO nanomaterials showed enhanced photodecolorization efficiency due to FRET, charge separation, and defect state density. This study employs oxidative polymerization, co-precipitation, and ex-situ surface capping techniques to fabricate pristine PMMA, ZnO, and PMMA-capped ZnO specimens with varying PMMA concentrations. X-ray diffraction reveals reduced directional growth of ZnO, while Fourier transform infrared spectroscopy confirms PMMA chain bonding with ZnO in PMMA-capped specimens. Scanning electron microscopy illustrates decreased average length and thickness of ZnO nanoplates post-surface modification, indicating a robust interaction between PMMA and ZnO. X-ray photoelectron spectroscopy identifies suppressed defects, including zinc interstitials and oxygen vacancies, affirming ZnO surface capping by PMMA. Absorption spectra display a blue shift in band-edge or increased bandgap, attributed to the combined effects of band alignment offset and reduced oxygen vacancy states. Luminescence spectra show gradual quenching linked to PMMA content increase, with defect-related emission suppression attributed to ZnO surface capping. UV emission suppression is ascribed to donor concentration-dependent Förster resonance energy transfer (FRET) from PMMA to ZnO. Photocatalytic tests reveal enhanced efficiency in PMMA-capped ZnO catalysts attributed to synergies involving charge separation, bulk recombination centers, oxygen vacancy states, and FRET. Efficiency improves with higher PMMA content, aligning with changes in emission intensity. The study demonstrates emission intensities' tunability through surface capping and donor concentration-dependent FRET, ultimately influencing degradation efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel grafted silica nanoparticles were prepared. • Novel green chemical mechanical polishing was developed. • A simple slurry was proposed, including only grafted silica and sodium carbonate. • Atomic surface is achieved on silicon surface. Atomic surface of silicon (Si) wafers is highly desired for integrated circuit (IC) industry. To meet this demand, traditional chemical mechanical polishing usually employs noxious slurries with complex compositions, containing oxidant, dispersant, inhibitor, surfactant, etc., resulting in the pollution of the environment and high-cost post-treatments. To settle this challenge, a novel green chemical mechanical polishing was developed, only including grafted silica nanoparticles and sodium carbonate. After CMP, surface roughness Sa of 0.219 and 0.247 nm are achieved on Si wafers using amine and methyl modified nanoparticles, respectively, corresponding to material removal rate (MRR) of 132.53 and 84.82 nm/min. Amino-modified nanoparticles increase 18.2 % MRR, and methyl modified ones reduce 24.4 % MRR, compared with those of unmodified nanoparticles. X-ray photoelectron spectroscopy reveals that amino-grafted nanoparticles have strong improvement for chemical reactions during CMP. Density functional theory calculations garner the electrostatic potential energy of 4.884 and 6.753 eV for amine and methyl-modified nanoparticles, respectively, corresponding to high and low effects for MRR. This work provides a new avenue to develop novel green simple CMP for Si wafers, reducing the pollution and cost for post-treatments. [ABSTRACT FROM AUTHOR]

[Display omitted] • The HEA samples have a BCC and HCP crystal structure. • The MAO process produced a porous anodic layer. • MAO incorporated bioactive elements (CA, P, and Mg) into the film. • The increase in voltage in the MAO process led to an increase in the contact angle. This study evaluated the effect of alloying elements, applied voltage, and bioactive species (Ca, P, and Mg) enrichment during the micro-arc oxidation (MAO) treatment of novel high entropy alloys (HEAs) targeted for biomedical applications. The non-equiatomic TiZrNbTaMo (TaMo), TiZrNbTaMn (TaMn), and TiZrNbFeMo (FeMo) samples were submitted to MAO treatment at distinct voltages (100, 200, and 300 V), then their chemical, phase, and morphological aspects were evaluated by x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and scanning and transmission electron microscopy (SEM and TEM). Finally, the preliminary physicochemical behavior regarding contact angle and surface energy in distilled water at room temperature was evaluated. The results indicated that the alloying elements played a global role in the bulk's phase composition, possessing distinct proportions of BCC and HCP phases. The MAO-treated surfaces depicted different mechanisms of anodic oxide growth and dielectric breakdown, forming the typical porous surface at distinct applied voltages. The bioactive species (Ca, P, and Mg) were gradually enriched in the oxide layer, composed of distinct nano-crystalline and amorphous layers that are typical of MAO-treated surfaces. As a result, roughness, contact angle and surface energy values of the MAO-treated samples were affected by the applied voltage and the bulk's chemical composition, indicating potential for use in the biomedical field, especially as long-term implants and bone fixation devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • To develop four van der Waal heterojunctions, we vertically stacked hexagonal Boron Nitride (h-BN) and four Transition metal dichalcogenides (TMDCs), namely h-BN/WS2, h-BN/WSe 2, h-BN/MoS 2 and h-BN/MoSe2, using a wet transfer technique. • X-ray photoelectron spectroscopy (XPS) measurements were used to determine the Valence Band Offset (VBO) values of the heterojunctions. • It is important to note that each heterojunction was a type I heterojunction. • The study illustrate the impact of chalcogen on VBO values in heterojunctions and found that VBO values increase when chalcogen transitions from S to Se in TMDCs. In order to analyze the effect of the chalcogen on the band alignment of the Transition metal dichalcogenides (TMDCs) and hexagonal Boron Nitride (h-BN) heterojunction, we fabricated the h-BN/TMDCs heterojunction by vertically stacking mono-layer h-BN and multi-layer TMDCs by the wet transfer method. The four heterojunctions are h-BN/WS 2 , h-BN/WSe 2 , h-BN/MoS 2 and h-BN/MoSe 2. X-ray photoelectron spectroscopy (XPS) has been employed to ascertain the Valence Band Offset (VBO) at the junctions created among these heterojunctions. All heterojunction band alignment styles are type-I. When the chalcogen changes from S to Se, the heterojunction VBO values increase. Specifically, in case of h-BN/WS 2 and h-BN/WSe 2 the VBO is 2.42 eV and 2.81 eV, respectively, and the magnitude of the difference is 0.39 eV. In the same case for h-BN/MoS 2 and h-BN/MoSe 2 the VBO is 2.52 eV and 2.55 eV, respectively, and the magnitude of the difference is 0.03 eV. The aforementioned research has obtained the band alignment for four heterojunctions, which provides a valuable reference for the design and analysis of the correlation devices in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced activity is achieved despite the Type-I-like band structure in FIS@ZIS. • A novel ohmic-like charge transfer mechanism is introduced for charge utilization in Type-I junction. • The band bending and IEF provides driving force for charge transfer at the FIS@ZIS interface. • Experimental evidence confirms the spatial separation of photo-induced charges. Manipulating charge transfer pathways in Type-I heterojunctions is essential to address the mismatched energy bands and the often-neglected internal electric field (IEF). This study reports the successful engineering of a Type-I FeIn 2 S 4 @ZnIn 2 S 4 heterojunction exhibiting an ohmic-like charge transfer mechanism, driven by the IEF arising from considerable Fermi level differences. The ohmic-like Type-I junction facilitates efficient electron transfer from ZnIn 2 S 4 to FeIn 2 S 4 and preserves the oxidizing holes in ZnIn 2 S 4 for effective scavenger oxidation. This unique feature prevents the inefficient charge separation commonly observed in conventional Type-I heterojunctions. Due to the advantageous ohmic-like electron transfer, an optimized composition of FeIn 2 S 4 @ZnIn 2 S 4 with a weight percentage of 10 % FeIn 2 S 4 achieves a notable hydrogen evolution rate of 4.21 mmol g-1h−1, six times higher than isolated ZnIn 2 S 4. Furthermore, the validation of the ohmic-like charge transfer mechanism is supported by theoretical analyses and advanced characterization techniques, including in-situ X-ray photoelectron spectroscopy (XPS), Kelvin probe force microscopy (KPFM), and surface photovoltage (SPV) measurements. This present study introduces a pioneering prototype that shows the successful incorporation of the desired charge transfer pathway in a Type-I heterojunction through the implementation of an IEF regulation strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Successful integration of two dissimilar semiconductors: GaAs and β -Ga 2 O 3. • XPS analysis is conducted for band alignment construction. • The experimental band alignment matches the theoretical model. • The resulting GaAs/ β -Ga 2 O 3 p-n diodes exhibit remarkable rectifying behaviors. Beta phase-gallium oxide (β -Ga 2 O 3) is an emerging ultrawide bandgap semiconductor but lacks efficient p-type doping, which hinders development of high-performance bipolar heterojunction devices. This study introduces the synthesis and characterization of a monocrystalline GaAs/ β -Ga 2 O 3 p-n heterojunction, employing advanced semiconductor grafting technology. The heterojunction was innovatively fabricated by grafting a p-type GaAs single crystal nanomembrane to an Al 2 O 3 -coated n-type β -Ga 2 O 3 epitaxial substrate. The synthesized heterojunction was comprehensively characterized. The band alignment of grafted GaAs/ β -Ga 2 O 3 p-n heterojunction was experimentally constructed through X-ray photoelectron spectroscopy (XPS), and the result is in accordance with the theorical prediction based on the electron affinity rule. The resulting GaAs/ β -Ga 2 O 3 p-n diodes built on this heterojunction exhibit remarkable performance metrics, including an ideality factor of 1.23, a high rectification ratio of 8.04 × 109 at ± 4 V, and a turn on voltage at 2.35 V. Furthermore, at + 5 V, the diode displays a large current density of 2500 A/cm2 along with a low ON resistance of 2 mΩ∙cm2. This study marks the first successful demonstration of a high-quality grafted GaAs/ β -Ga 2 O 3 p-n heterojunction, establishing a critical building block for the further development of bipolar Ga 2 O 3 -based device applications such as diodes, transistors, and thyristors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of in-situ AlOx passivation on the stability of InSnO transistors has been investigated. • The in-situ AlOx-passivated InSnO transistors demonstrated satisfactory electrical performance. • For the in-situ AlOx-passivated InSnO transistors, the total trap density is notably decreased. • The NBS, PBS and low-frequency noise of InSnO transistors are significantly improved. In this study, we present the impact of an ultrathin in-situ AlO x passivation layer on the electrical performance and stability of InSnO (ITO) transistors. Devices incorporating an ultrathin (∼2 nm) AlO x passivation layer demonstrate satisfactory electrical performance and stability, characterized by a decent field-effect mobility, enhancement mode operation, notably reduced subthreshold swing, negligible hysteresis, and, notably, a significantly reduced threshold voltage shift under negative bias stress (NBS) and positive bias stress (PBS), respectively. The total trap density (N tot), extracted through the sub-threshold slope, and the trap density (N t), measured using low-frequency noise (LFN) for the AlO x -passivated ITO transistors, are significantly decreased. Those improvements can be attributed to the suppression of oxygen vacancy formation during the reactively-sputtered AlO x and subsequent annealing processes, as demonstrated by comparing the in-depth X-ray photoelectron spectroscopy (XPS) results of the AlO x -passivated and un-passivated ITO films. These results underscore the potential of in-situ reactively-sputtered ultrathin AlO x passivation layers to enhance the stability of thin-film transistors with In-rich channels. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanostructured β −Ga 2 O 3 sensors are fabricated by simple wet chemistry methods. • NAP-XPS reveals the low-temperature gas sensing mechanisms in β-Ga 2 O 3 nanorods. • Low-temperature ethanol detection by β −Ga 2 O 3 nanorods is discussed in detail. Ga 2 O 3 is a promising gas-sensing material that can operate over a wide temperature range. However, despite its relevance for practical applications, there is a lack of understanding regarding its sensing mechanism at temperatures below 800 °C. To reveal the sensing mechanism, GaOOH nanorods were grown on β-Ga 2 O 3 seed layers by chemical bath deposition, then converted to β-Ga 2 O 3 by annealing in the air at 500 °C, and the surface properties were investigated by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) in the presence of oxidizing/reducing gases. Time-stable shifts in the XPS spectra were used to estimate the relative changes in conductivity in compliance with the ionosorption model. Our results indicate that the sensing mechanism at lower temperatures is governed by redox reactions, leading to an increase/decrease in the conductivity for reducing/oxidizing gases. Furthermore, we provide a detailed description of the ethanol-sensing mechanism at different temperatures. [ABSTRACT FROM AUTHOR]

In this research, we proposed a simple cyclic voltammetry method to electrodeposition of hierarchical porous PbSe on single-layer graphene film. The porous structure with large surface to volume ratio will enhance the light absorption ability after effectively sensitized in oxygen atmosphere. Furthermore, oxygen-sensitized processes create electron traps at grain boundaries, extending the lifetime of the hole carrier and improving photoconductive sensitivity. This work highlights the low cost and effective electrodeposition strategy for constructing hierarchical porous structure with further application in infrared photodetection. [Display omitted] • Electrodeposition hierarchical porous PbSe on single-layer graphene film. • Porous structure can be effectively sensitized in oxygen atmosphere. • Hybrid structure will enhance the light absorption ability. Lead selenide (PbSe) has been extensively studied as an infrared detection material capable of operating at room temperature. In this research, we proposed a simple cyclic voltammetry (CV) electrodeposition of hierarchical porous PbSe on single-layer graphene film. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy were used to evaluate the physical and surface characteristics of porous PbSe films. The porous structure with large surface to volume ratio will enhance the light absorption ability after effectively sensitized in oxygen atmosphere. Furthermore, oxygen-sensitized processes create electron traps at grain boundaries, extending the lifetime of the hole carrier and improving photoconductive sensitivity. At room temperature, the porous PbSe/graphene photodetector exhibit a responsivity of 12.3 A/W, a detectivity of 5.95 * 108 cm Hz1/2W−1 (@1 kHz) at 1.55 µm, and a responsivity of 15.2 A/W, a detectivity of 1.4 * 109 cm Hz1/2W−1(@1 kHz) at 2.7 µm. This work highlights the low cost and effective electrodeposition strategy for constructing hierarchical porous structure with further application in infrared photodetection. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel SERS sensor based on calcium silicate hydrate with silver was developed. • Fabrication of the sensor involved laser irradiation of the sample at 355 and 532 nm. • An increase in the concentration of metallic Ag on the material surface was responsible for the SERS response. • The composition of the sensor opens the possibility of extending the applicability of SERS to the concrete field. This study aims at synthesizing a novel Surface-Enhanced Raman Spectroscopy (SERS) sensor based on a nanostructured substrate, calcium silicate hydrate (C-S-H), the main hydration product of Portland cement. The procedure involves first the incorporation of silver within the nanostructure of the gel (C-S-Ag-H) and second the modification of the surface of pellets of the newly synthesized material by laser irradiation at 532 nm or 355 nm. The assessment of the SERS activity revealed no amplification of the organic molecule rhodamine B (RdB) signal, used as a probe, on the C-S-Ag-H before laser irradiation. However, after laser irradiation, the SERS effect was comparable to that of reference colloidal Ag nanoparticles (NPs). This SERS response is attributed to an increase in the concentration of metallic silver on the surface of the C-S-Ag-H pellets upon laser irradiation and material ablation as revealed by X-ray Photoelectron Spectroscopy (XPS). Further enhancement of the SERS signals was induced by depositing colloidal Ag NPs on the irradiated pellets, giving rise to interparticle hot spots where the electromagnetic field is further intensified. [ABSTRACT FROM AUTHOR]

[Display omitted] • C 3 N 4 nanosheets with expansive delocalized π electron structure and enriched N vacancies was synthesized successfully. • Characterization of delocalized π electron structure and enriched N vacancies. • Insights into the relationship between chemical structure changes and delocalized π electron structure. For improving the essential photocatalytic H 2 evolution activity of C 3 N 4 , strategies via simultaneously modulating the delocalized π electron structure and defects are feasible but challenging. Herein, a C 3 N 4 nanosheets material defined as C 3 N 4 -NS-RN with expansive delocalized π electron structure and enriched N vacancies was synthesized successfully via a facile post heat treatment. Firstly, a precursor of C 3 N 4 nanosheets defined as C 3 N 4 -NS-PN with corrugate tri-s-triazine basal plane and abundant NH x groups in aromatic conjugate system was prepared. Fourier transform infrared spectra, X-ray photoelectron spectroscopy and nuclear magnetic resonance demonstrated C 3 N 4 -NS-PN had an enhanced delocalized π electron configuration via van der Waals coupling effect. However, the delocalization of π electrons across the basal plane was disturbed due to the corrugate conjugate plane. For further reconstructing delocalized π electron structure of C 3 N 4 -NS-PN, C 3 N 4 -NS-RN was synthesized via eliminating NH x groups and introducing enriched N vacancies in the conjugate system. Photoluminescence spectroscopy and electron paramagnetic resonance verified C 3 N 4 -NS-RN had an enhanced delocalized π electrons structure than C 3 N 4 -NS-PN. The photocatalytic H 2 evolution activity of C 3 N 4 -NS-RN was steady and was about 1.8 and 6.1 times of C 3 N 4 -NS-PN and the bulk C 3 N 4 , respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1000 days immersion study of PMMA-silica coatings on Al alloys in 0.6 M NaCl solution. • Water uptake of less than 0.7 vol% assessed by analysis of electrochemical impedance data. • Modeling of electrochemical impedance data revealed a "less-Fickian" diffusion coefficient. • The efficient diffusion barrier against corrosive species results in high corrosion resistance. • Nanostructural changes do not significantly affect the long-term anticorrosive performance. Poly (methyl methacrylate) (PMMA)-silica coatings form a few micrometers thick anti-corrosive barrier that blocks corrosive species when exposed to harsh environments. Their excellent anti-corrosive performance stands out for protecting metal alloys immersed in seawater for long periods (>2 years), making them compliant for applications in the marine, aeronautical, and automotive industries. A key approach to understanding the degradation of high-performance coatings over time consists of analyzing their water uptake-induced structural changes. This work examines in detail the uptake and structural modification of PMMA-silica coatings on Al alloys immersed for more than 1000 days in 3.5 wt% NaCl solution. Gravimetry, thermal analysis, infrared spectroscopy and electrochemical impedance spectroscopy (EIS) were employed to monitor the evolution of coated samples. Nuclear magnetic resonance, X-ray photoelectron spectroscopy, electron and atomic force microscopies before and after immersion indicate a slight leaching-induced surface roughening due to silica hydrolysis. These findings comply with the low uptake values (∼0.6 vol%) and a less-Fickian diffusion coefficient obtained from modelling of the EIS data. The high impedance modulus (>GΩ) is related to the highly cross-linked structure, resulting in a very low permeation rate of the electrolyte. The applied methodology is of crucial importance for establishing a standardized analysis for high-performance protective coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chemoselective adsorption of aldehydes on –NH 2 functional groups is confirmed. • Chemisorption of aldehydes on –NH 2 and –OH was investigated by DFT calculations. • Undecanal on nitrides significantly inhibits deposition against Ru ALD. • AS-ALD of Ru thin films is successfully demonstrated on patterned TiN/SiO 2. • This approach holds promise for AS-ALD showcasing metal/dielectric selectivity. Area-selective atomic layer deposition (AS-ALD) on pre-defined areas is of crucial importance nowadays in significantly reducing complexities associated with current top-down fabrication processes. In this work, we report the effects of surface modification using various alkyl aldehyde inhibitors with different chain lengths—hexanal, decanal, and undecanal—on nitride surfaces such as TiN and SiN to achieve AS-ALD. On the basis of density functional theory calculations and experimental analysis, including water contact angle and X-ray photoelectron spectroscopy, it is evident that aldehydes would chemo-selectively react with the –NH 2 functional groups present on the nitride surfaces. Then, we further investigate their blocking ability against subsequent Ru ALD, a promising next-generation electrode material. It is worth noting that the Ru deposition thickness decreased by 4–10 nm with the presence of undecanal adsorbed on SiN and TiN substrates. Finally, we successfully demonstrate AS-ALD of Ru thin films over 8 nm on a patterned TiN/SiO 2 substrate. These results hold potential for applications in bottom-up nanofabrication techniques for next-generation nanoelectronic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Improvement of surface properties through laser irradiation. • Identify the origin of Si surface defect formation due to laser irradiation. • Effective protection from laser damage by forming a high-density protective layer. • Improved surface properties reduce the proportion of suboxide generated by ALD. This research investigates surface damage in electronic devices from laser irradiation, particularly focusing on voids, cracks, and vacancies. We discovered that applying a high-density ultrathin SiO 2 layer effectively prevents such defects. Atomic Force Microscopy (AFM) analysis showed a significant reduction in surface roughness, with the R q factor value dropping to 0.158 nm in samples coated with this SiO 2 layer. Additionally, X-ray Photoelectron Spectroscopy (XPS) was used to study suboxide formation in the Al 2 O 3 /Si structure, revealing insights into defect origins. Electrical tests indicated a substantial decrease in laser-induced damage, evidenced by a leakage current density reduction to 2.4 × 10−6 A/cm2, markedly lower than uncoated samples. Post-metallization annealing (PMA) further improved results, with the interface state density decreasing to 0.63 × 1012 atoms eV−1 cm−2. Our findings highlight the effectiveness of the high-density ultrathin SiO 2 layer in mitigating surface defects caused by continuous wave (CW) laser irradiation, promising significant advancements in electronic device manufacturing through potential application in CW laser annealing processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • WB 5-x as efficient cocatalyst for photocatalytic applications is proposed. • 5 wt% WB 5-x -WB 2 /TiO 2 possesses 23 times higher H 2 production rate than TiO 2 (81 H 2 µmol h−1 g cat –1) • 10 wt% WB 5-x -WB 2 /TiO 2 shows 4 times higher CO 2 RR rate than TiO 2 (108 µmol h−1 g cat –1) • New application direction for transition metal borides in photocatalysis is proposed. Catalytic reactions play an important role in modern industry as almost 90 % of the chemical industry is based on catalytic reactions. The development of new, more efficient catalysts will allow significant advances in chemical production, but still remains a rather challenging problem for materials scientists. Here, we have proposed and investigated a new composite photocatalyst based on WB 5-x -WB 2 and TiO 2 for H 2 evolution from aqueous ethanol solution and CO 2 reduction under visible light irradiation (410 nm). New composite photocatalysts WB 5-x -WB 2 /TiO 2 were synthesized and characterized by X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Photocatalytic measurements show that the maximum activity of the composite photocatalyst 4 and 23 times higher than the activity of unmodified TiO 2 in CO 2 reduction and H 2 evolution, respectively. Density functional calculations of the proposed reaction are in agreement with the provided experiments confirming the higher efficiency of the modified catalyst compared to TiO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • A model for energy-dependent XPS for depth profiling of chemical bonding. • N-Terminated diamonds obtained by Microwave Plasma show no sp2 defects. • A ∼5 % coverage of graphene-like islands is present atop the diamond surface. • The energy level of N surface states is determined within the diamond bandgap. • The high energy of the unoccupied surface states could help to stabilize NV- centers. Nitrogen-terminated diamonds hold promise for stabilizing near-surface NV− centers, which is essential for reliable quantum sensing. Among various surface preparation methods, microwave (MW) nitrogen plasma, known for its minimal surface damage, appears as the most effective choice. In this investigation, we explore the nature of nitrogen bonding of polycrystalline diamond (PCD) surfaces exposed to MW nitrogen plasma using X-ray Photoelectron Spectroscopy (XPS) depth profiling and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy at the C K - and N K -edges. XPS depth profiling with atomic resolution, achieved by varying the probing photon energy using synchrotron radiation and supported by a physical model considering the associated inelastic mean free path, suggests a surface of almost fully saturated nitrogen in two main bonding configurations of similar contribution and a low coverage of ∼5 % of graphene-like islands residing atop the nitrogen-terminated diamond surface. The thermal stability of these surface groups is monitored by in situ annealing up to 700 °C. The depth profiles reveal that nitrogen atoms do not diffuse in the diamond crystal, resulting in excellent diamond crystallinity in the first atomic planes below the surface. C K -edge NEXAFS analysis reveals the position of unoccupied surface states within the diamond bandgap, opening new perspective on the stabilization of near-surface NV− centers. [ABSTRACT FROM AUTHOR]

[Display omitted] • PTFE was modified with quaternary ammonium groups by plasma-based methods. • NH 3 plasma was employed to directly generate superficial amino groups on PTFE. • O 2 plasma combined with silanization (APTES) led to amino moieties at PTFE surface. • Amino groups were quaternized (alkylation with CH 3 -I) to give quaternary ammonium groups. • Functionalization of PTFE was proven by XPS and zeta potential measurements. Hydrogen produced by electrolysis using renewable energy sources offers a zero-emission alternative to fossil-based sources providing high efficiencies in all energy sectors. Anion Exchange Membrane Water Electrolysis (AEM-WE) combines the advantages of the established technologies, alkaline (AEL) and proton exchange membrane (PEM) water electrolysis. However, AEM-WE still requires optimization, especially with regard to the membrane, catalysts and electrode structure. In this contribution we focus on the improvement of PTFE-based binders for AEM-WE membranes, which provide high chemical stability but lack the required ion conductivity. Thus, the functionalization of PTFE towards quaternary ammonium moieties (QAS) was investigated employing two approaches: (i) NH 3 -plasma treatment and (ii) O 2 -plasma with subsequent coupling of aminosilanes. Finally, the surface coupled amino groups were converted into QAS via alkylation with iodomethane (CH 3 -I), introducing ion conductivity. Successful functionalization was proved by X-ray photoelectron spectroscopy (XPS), displaying changes in the surface composition of PTFE surfaces such as the introduction of amino groups at the expense of fluorine, and the increase in surface carbon content upon alkylation. Furthermore, contact angle measurements revealed increased wettability with water due to the introduction of the polar surface functionalities, while zeta potential measurements confirmed the increase of positive surface charges along the modification processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel collector IBATC was synthesized and used in the flotation separation of chalcopyrite, pyrite and sphalerite. • IBATC can effectively separate chalcopyrite from sphalerite and pyrite with pH of 9.5–10 and concentrate of 30–40 mg/L. • IBATC chemically adsorbed on chalcopyrite surface, whereas physically adsorbed on sphalerite and pyrite surface. • IBATC bonded with Cu sites on chalcopyrite surface through S atoms. In this paper, a new collector, named O-isobutyl-N-allyl thionocarbamate (IBATC), was synthesized, and the structure was characterized by Fourier Transform Infrared Spectrometer (FTIR) and 1H NMR, 13C NMR analysis. The collection performance of IBATC was evaluated by flotation tests and interaction mechanism was investigated by means of adsorption amount, zeta potential measurements, FTIR, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. The flotation tests results proved that IBATC was inclined to collect chalcopyrite compared with pyrite and sphalerite. Especially in the pH range of 9.5–10 and IBATC concentrate of 30–40 mg/L, the recovery of chalcopyrite exhibited more than 80 %. The adsorption amount and zeta potential measurements showed that IBATC had a greater orientation to chalcopyrite. FTIR and XPS analysis demonstrated IBATC chemically adsorbed on chalcopyrite surface, whereas physically adsorbed on pyrite and sphalerite. Further, DFT calculation of the interaction between IBATC and chalcopyrite proved that S atom of IBATC donated electrons to Cu sites on chalcopyrite surface and the adsorption energy was −19.45 kcal/mol, referring to an exothermic reaction. As a result, IBATC showed great capacity for the separation flotation of chalcopyrite, pyrite and sphalerite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structural and morphological characterization of Pulsed Laser deposited BiFeO 3 films at different deposition temperature. • Chemical state analysis along with absorption and emission studies of films. • Modulation of defect type and density with deposition temperature. • Estimation of defect levels, carrier type and defect densities. This research investigates the structural, topological, electrical and optical properties of pulsed laser deposited polycrystalline BiFeO 3 thin films on silicon and glass substrate at varying deposition temperatures ranging from 400 °C to 700 °C. X-ray diffraction confirm rhombohedral phase and X-ray photoelectron spectroscopy reveals stoichiometric BiFeO 3 films. The optical bandgap of thin films obtained from absorption spectra increases with the substrate temperature. Photoluminescence emission spectrum reveals the defects and Atomic Force Microscopy analysis bring out the surface topography and crystallinity improvement with temperature. The charge transport studies reveal a transition in conductivity from n-type at lower deposition temperature to p-type at higher deposition temperature, attributed to oxygen and bismuth vacancies respectively. The intricate understanding of conductivity tuning and the leaky nature of BiFeO 3 thin film opens avenues for applications in non-volatile memories, particularly neuromorphic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Changes in surface chemistry of a bulk metallic glass upon sliding were evaluated. • The composition of the surface oxide is not affected by tribological conditions. • The oxide thickness is affected by the stress level at contact the trailing edge. Bulk metallic glasses (BMGs) are promising structural materials owing to their high elastic limit and yield strength-to-weight ratio. While BMGs also exhibit attractive tribological properties (e.g. , high wear resistance), the scientific basis for this behavior is not yet established. In particular, tribologically-induced changes in surface chemistry upon sliding are still an open topic of research. Here, we evaluated by X-ray photoelectron spectroscopy (XPS) the evolution of the surface chemistry of Vitreloy 105 (a Zr-rich BMG) upon sliding under different contact conditions against a tungsten carbide countersurface. The spectroscopic results indicate that the relative fraction of the metallic elements in the near-surface region is not affected by the sliding speed when the applied contact pressure is lower than 1.37 GPa, while a decrease in metallic zirconium was observed at lower sliding speeds and higher applied contact pressure (i.e. , 1.71 GPa). Based on the spectroscopic results, a model is proposed for the effect of mechanical stress on the extent of oxidation of the near-surface region of Zr-based BMGs. The results of this work provide novel insights into the surface phenomena occurring on BMGs upon sliding and add significantly to our understanding of the tribological response of this class of promising structural materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe 3 O 4 @MIL-101@PPys enhanced peroxidase activity was quickly achieved. • This strategy first enabled sensitive cascaded-catalytic determining of norfloxacin (NOR). • Colorimetric and sensing platform was established in an intelligent method conveniently. • The cascaded-catalytic detection mechanism was further explored. Nanozymes based on default engineering have garnered considerable interest for their ability to effectively imitate natural enzyme catalysis settings for detection. With the widespread use of quinolone antibiotics, it is worth noting that the antibiotic drugs represented by norfloxacin (NOR) are concentration-dependent when used. Therefore, residual or dosage differences in the body can lead to some central toxicity hazards, so monitoring and detection are necessary. Herein, we reported Fe 3 O 4 @MIL-101@polypyrroles (PPys) nanozymes with default engineering, which possessed a porous core–shell structure with Fe 3 O 4 as the core and MIL-101 and PPys as the shells in sequence. X-Ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculation were to guide and analyze the catalytic pathway of peroxidase-like activity. Furthermore, a versatile intelligent colorimetric and sensing platform has been established to achieve sensitive cascaded-catalytic determining norfloxacin (NOR). In addition, NOR has a lower threshold of acceptability detection of 0.14 μM, which is better than the interpreted detection methods. We have firstly explored the detection mechanisms of ascorbate (H 2 A) and NOR and discovered that NOR could selectively oxidize Fe2+ and support Bi-Bi mechanisms in the process of H 2 O 2 catalysis. Excellent guidelines for the design of multifunctional nanozyme catalysts were provided by the inquiry. [ABSTRACT FROM AUTHOR]

[Display omitted] • TRP achieved a better activation effect for smithsonite flotation. • TRP reacted strongly with zinc atoms on the surface of smithsonite. • Trp increased the adsorption of NaOL on the surface of smithsonite. • DFT calculations showed that the carboxyl O atom in Trp coordinated with Zn on the surface of smithsonite. Utilizing an efficient activator is an efficient solution to overcome the low recovery flotation of zinc oxide ore. We proposed amino acids as new high-efficiency biological activators for zinc oxide ore flotation and systematically studied the effects of amino acids as activators in the flotation of zinc oxide ore. Fourier transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and density functional theory (DFT) calculations were conducted to reveal the activation mechanism of amino acids in smithsonite flotation. The results showed that tryptophan (Trp) significantly promoted the floatability of smithsonite by coordinating with zinc sites on the surface of smithsonite. The addition of Trp broke the Zn-O bonds in the crystal and exposed more highly active Zn on the crystal surface, which easily reacted with sodium oleate. At the same time, Trp increased the concentration of Zn2+ in the pulp, and an appropriate amount of Zn2+ in the solution owned a certain activation effect, which finally improved the adsorption of NaOL on the surface of smithsonite. DFT showed that Trp interacted strongly with smithsonite, and the carboxyl O atom of Trp coordinated with Zn on the surface of smithsonite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Study of the effects of NF 3 or F 2 gas annealing on epitaxially grown GaN by hard x-ray photo electron spectroscopy (HAXPES). • NF 3 or F 2 gas annealing on the Pt/GaN interface studied by HAXPES. • NF 3 gas annealing forms Ga–F x species not only in the bare GaN surface but also in the Pt/GaN interface. • F 2 gas annealing forms Ga–F x species only in the bare GaN surface. • The plasma sputtering process of Pt deposition removed F from the bare GaN surface. The effects of NF 3 or F 2 gas annealing on epitaxially grown GaN and its interface with sputter-deposited Pt were investigated using hard X-ray photoelectron spectroscopy. Annealing GaN and Pt/GaN samples in an NF 3 atmosphere led to the emergence of prominent F 1 s peaks and chemically shifted Ga 2 p peaks, indicating the efficient formation of Ga–F x species not only in the bare GaN surface but also in the Pt/GaN interface, even when the NF 3 treatment was performed after the Pt was deposited. By contrast, F 2 annealing also led to the fluorination of the GaN surface and nonfluorination of the Pt/GaN interface. Although the plasma sputtering process removed F from the surface, band shifts were observed when the treatment conditions were varied. The findings in this study suggest that NF 3 treatment is an effective post-processing method for fluorinating GaN-based systems before or after metal deposition. [ABSTRACT FROM AUTHOR]

[Display omitted] Molybdenum disulfide, a two-dimensional semiconductor, has found broad applications in various functional devices. Currently, developing a reliable method for growing wafer-scale monolayer molybdenum disulfide presents a significant challenge in its integration into the contemporary semiconductor industry. This study employed low-energy reactive magnetron sputtering with hydrogen disulfide gas to deposit wafer-scale epitaxial few-layer and monolayer molybdenum disulfide on c -sapphire substrates. The epitaxial molybdenum disulfide nano-thin film was examined using scanning nano-probe X-ray diffraction technique, revealing a single grain size of no less than 50 × 50 μm2. Furthermore, the growth of monolayer molybdenum disulfide on both c -sapphire and thermal silicon oxide substrates was verified through Raman microscope. Measurements of photoluminescence and X-ray photoelectron spectroscopy also confirmed the monolayer state of the sputtered nano-thin films. This study suggests that reactive magnetron sputtering with hydrogen disulfide gas offers a cost-effective, scalable method for growing large-area molybdenum disulfide nano-thin films, thereby holding significant potential for practical semiconductor industrial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Small Ni 1−x Mn x Co 2 O 4 nanoparticles were synthesized by low-temperature gel combustion. • All the nanoparticles revealed strong catalytic performance in 4-nitrophenol reduction. • The catalytic performance of Ni 0.5 Mn 0.5 Co 2 O 4 nanoparticles was superior to NiCo 2 O 4 and MnCo 2 O 4 nanoparticles. • >90 % of 4-nitrophenol could be reduced in 12 min. • The anomalous catalytic behaviors of the nanostructures in repeated cycles were explained. Developing efficient catalysts is one of the challenging tasks for protecting our environment from contamination. Here we present the synthesis of Ni 1−x Mn x Co 2 O 4 , noble-metal free multimetallic oxide nanoparticles of 9.5–25.0 nm average sizes by a low-temperature gel combustion method and their utilization as catalysts for rapid reduction of 4-nitrophenol (4-NP) to aminophenol (AP). Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and vibrating sample magnetometry were used for the characterization of the nanostructures. All the nanostructures revealed strong catalytic performance in the reduction of 4-NP, and the performance of Ni 0.5 Mn 0.5 Co 2 O 4 nanoparticles was superior (>90 % reduction in 12 min) to that of NiCo 2 O 4 and MnCo 2 O 4 nanoparticles. While the 4-NP reduction process followed a pseudo-first-order kinetics for all the catalysts, the reduction efficiency of the samples manifested a complex trend from cycle to cycle. The anomalous catalytic behavior of the nanostructures in 4-NP degradation has been explained. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple and cost-effective synthesis of MoS 2 @MWCNTs by wet chemical method. • The MoS 2 @MWCNTs has improved surface area attributed in its surface imperfections and defects. • The MoS 2 @MWCNTs selectively detects picric acid (PA) in the presence of common water and structurally analogues interferants. • The synthesized electrocatalyst shows lower LoD with wide linear range. • The recyclability, reproducibility, repeatability experiments prove efficacy of electrocatalyst and applied for real samples. Nitrophenols are industrially versatile yet environmentally detrimental compounds. Herein, we have synthesised molybdenum sulphide based dichalcogenide supported multiwalled carbon nanotubes i.e. MoS 2 @MWCNTs electrocatalyst by simple wet chemical method for PA determination. The successful decoration of MoS 2 over MWCNTs were confirmed by various characterizations techniques including scanning electron microscopy (SEM) shows MoS 2 layers grown on MWCNTs and having average size is –80 nm. Energy dispersive X-ray analysis (EDAX) reveals elements are homogenously distributed in nanocomposite. High resolution-transmission electron microscopy (HR-TEM) shows increase in average diameter after decoration of MoS 2 over MWCNTs from 30 nm to 70 nm. The Fourier transform infrared (FT-IR) analysis suggests the presence of Mo-S stretching frequency at 605 cm−1 in addition to hydroxyl, carbonyl, C–C, C–O stretching frequencies are also observed. In Raman spectrum from apart D and G bands, the characteristic intense bands E 2g 1 and A 1g of MoS 2 were pointed towards presence of molybdenum and sulphur. The X-ray diffraction (XRD) confirms synthesised electrocatalyst is in hexagonal crystal structure with P63/mmc space group. The X-ray photoelectron spectroscopy (XPS) reveals that for Mo 3d is found to be two characteristics peaks at 231.2 eV and 233.2 eV corresponds to Mo4+ 3d 3/2 and 3d 5/2 respectively. The peak at 229 eV corresponds to S 2s. Whereas, the signal appears at 162.7 eV, 165 eV, 169 eV and 170 eV shows sulphur is in 2S 3/2 and 2S5 /2 states. Electrochemical performance was examined by cyclic voltammetry (CV) tests. The Electrocatalyst is highly selective, having appreciable anti-interference property, lower limit of detection (LoD), i.e., 0.5 μM with wide linear range. The low R ct and high k⁰ pointed that MoS 2 @MWCNTs performed better towards electrochemical detection of PA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Buffer layer-free direct integration of few-layer MoTe 2 on silicon. • Utilization of tellurium-rich substrate pre-wetting to suppress the contribution of surface dangling bonds. • The direct influence of growth temperature on the crystalline quality of the ultrathin films. • Role of molybdenum-adatom mobility and tellurium-desorption in different temperature regimes. • Influence of the film-stoichiometry on the metal-oxide formation for the grown two-dimensional film. Group-VI transition metal dichalcogenides (TMDCs) have garnered significant attention due to their novel properties in the two-dimensional realm. Among these TMDCs, MoTe 2 is a particularly intriguing material with a small difference between Gibbs free energies of its semiconducting and semimetallic phases, rendering it suitable for a wide array of applications. In this study, we report the molecular beam epitaxy (MBE) growth of 2H-MoTe 2 directly on a silicon (1 1 1) substrate, which holds great significance due to its compatibility with the existing integrated circuit industry. By employing a growth strategy involving a Te-rich silicon surface, we achieved the growth of high-quality, phase-pure 2H-MoTe 2 films. The effect of growth temperature on the film quality was investigated, revealing that the growth at 450 °C led to highly crystalline and layered growth. The thickness, roughness and stoichiometry of the grown films were characterized using spectroscopic ellipsometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Raman spectroscopy confirmed the presence of the desired 2H-phase for the grown films. The direct integration of MoTe 2 with silicon opens up exciting possibilities for its utilization in nanoelectronics and optoelectronics devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tm 2 O 3 passivation layer was successfully grown on 4H-SiC substrate. • Concentration of oxygen vacancies were reduced in the annealed passivation layer. • Curbing the existence of Tm-O suboxide in the annealed passivation layer. • Nitrogen ions were successfully incorporated into the Tm 2 O 3 lattice. • MOS characteristics for the Tm 2 O 3 /4H-SiC structure was systematically reported. Thulium oxide (Tm 2 O 3) passivation layer (PL) deposited on 4H-silicon carbide (SiC) that was subjected to postdeposition annealing at 700 °C in forming gas-oxygen-forming gas ambient was reported for the first time in this work. X-ray photoelectron spectroscopy characterization revealed the success of annealing process in minimizing the concentration of oxygen vacancies and also curbed the presence of Tm O suboxide bonding in the annealed Tm 2 O 3 PL. In addition, XPS characterization has also disclosed the incorporation of nitrogen ions into the Tm 2 O 3 lattice through the annealing process in which grazing incidence X-ray diffraction has also revealed the shift of detected peaks with regards to Tm 2 O 3 phases to small diffraction angles. Although X-ray reflectivity measurements have disclosed the formation of thicker SiO 2 interfacial layer (IL) for the annealed Tm 2 O 3 PL, the acquisition of a higher dielectric constant (k) by the annealed PL when compared to as-deposited PL has suggested that the formation of SiO 2 IL has minimal effect toward the k value of annealed PL. Metal-oxide-semiconductor characteristics of the annealed Tm 2 O 3 PL on 4H-SiC was systematically reported in this letter. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Nb is incorporated in the crystalline structure of WS 2 with and without KBr as a catalyst. • Nb-doped WS 2 monolayers exhibit a quenched photoresponse (down to 70%) intensity compared to pristine WS 2 monolayers. • VBM by XPS depicted a redshift that indicates the p-type doping of the WS 2 monolayers. • The Raman spectra show that disorder-related modes indicate an evolution of the density of defects. The in situ doping of tungsten disulfide (WS 2) monolayers with Niobium (Nb) atoms was obtained through the atmospheric pressure chemical vapor deposition (APCVD) method by controlling the Nb 2 O 5 and WO 3 precursors mass ratios. Samples were prepared employing the same growth parameters with and without the use of KBr salt as a catalyst. In both cases, the Nb incorporation quenches the luminescence intensity of the doped samples, and it depends on the Nb 2 O 5 :WO 3 mass ratio. X-ray photoelectron spectroscopy (XPS) measurements were performed, and the observed redshift at the Fermi level indicated p-type doping. Nb-doped WS 2 monolayers synthesized without the use of the catalyst have lower defect density, as revealed by a careful Raman analysis, and are free of agglomerates on their monolayers' basal plane. The use of KBr as the catalyst increases the average crystal size but also increases the disorder effects compared with samples prepared without the use of salt. The presence of agglomerates of impurities at the surface of doped samples was observed in samples prepared with the use of salt as a catalyst. The controlled synthesis of p-type WS 2 with low defect density is essential for developing electronic and photonic devices based on WS 2 material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Presenting a platform for reversible defect engineering in CeO 2 nanostructures. • VO 2 -CeO 2 bilayer samples were fabricated using atomic layer deposition. • The Low-temp. structural transition of VO 2 was utilized to induce stress in CeO 2. • VO 2 -CeO 2 underlying mechanism explained using in situ XPS and Raman spectroscopy. • We have achieved a remarkable Ce3+/Ce4+ ratio of 5.97 (Ce3+ ∼ 85%).. CeO 2 nanostructures (CNs) have found applications in many fields due to their unique oxidative regenerative properties. Unique properties of ceria have been linked to the defect structure of CNs which allows it to switch between two different oxidation states Ce3+ ↔Ce4+. As the defect structure of CNs is crucial therefore various methods were developed to engineer defects in CNs. However, precise, and reversible control over defect structure characters remains a persistent challenge. Herein, we report a method of temperature-controlled, reversible defect control in CeO 2 nanostructures through the fabrication of VO 2 -CeO 2 hetero-nano bilayers using atomic layer deposition (ALD). Reversible defect engineering in CeO 2 films has been demonstrated using X-ray photoelectron spectroscopy (XPS) studies with in situ heating and cooling. Defect levels were identified as variance in the Ce3+/Ce4+ oxidation states. A remarkable Ce3+/Ce4+ ratio of 5.97 (Ce3+ ∼ 85%) was obtained and modulated over a temperature range from room temperature to 90 °C. Raman studies with in situ heating and cooling were done to understand the mechanism behind the phenomenon further. In situ Ellipsometry, AFM, TEM, and STEM/EDS techniques were utilized to characterize the sample. Our temperature-controlled defect engineering platform for CeO 2 nanostructures can enable the precise designing of systems specific to various applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • LiCoO 2 films prepared by magnetron sputtering with good transport property and electrochemical performance. • Flexible graphene buffer layer modified interface characteristics of LCO/LAGP. • Analysis of interface impedance mechanism through the distribution of relaxation times (DRT). • Quasi-solid-state thin film lithium battery of LCO/G/LAGP/Li with a discharge specific capacity of 109.53 mAh·g−1. LiCoO 2 (LCO) films were successfully prepared using a radio frequency magnetron sputtering method, and the interface between the LCO cathode films and Li 1.5 Al 0.5 Ge 1.5 (PO 4) 3 (LAGP) solid electrolyte was modified by a graphene (G) buffer layer. The composition and morphology of the thin-film samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The LCO thin film annealed at 600 °C had excellent charge transport properties, respectively delivering initial charge and discharge specific capacities of 162.7 mAh·g−1 and 124.5 mAh·g−1 at 0.1C in a half-cell structure. Relaxation time distribution reconstruction impedance analysis and rate characteristic analysis of an LCO/G/LAGP/G/LCO symmetric cell demonstrated that the flexible graphene buffer layer effectively improved the contact impedance of the interface and structure stability of the active materials. After cycling for 1000 h at current densities of 0.02 mA·cm−2 and 0.5 mA·cm−2, the LCO/G/LAGP/G/LCO symmetric cell still maintained stable polarization voltages of 0.05 V and 0.7 V, respectively. In addition, an assembled LCO/G/LAGP/Li quasi-solid-state film lithium battery presented an initial discharge specific capacity of 109.53 mAh·g−1 at 0.1C, with a capacity retention rate of 71.86 % after 100 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • The surface phosphorus-induced strategy generates Ni-P(δ−) and Fe-P(δ−) stable bonding states. • The recombination of photoinduced electron-hole pairs was inhibited. • Enhanced absorbance intensity and absorption range. • Hydrogen evolution performance is 82 times of the NiFe-LDH. Light-driven semiconductor splitting of water for hydrogen production is becoming increasingly important in the direction of obtaining clean energy. In this study, high-temperature P-induced corrosion of NiFe-LDH was used to generate P-metal strong surface bonding states. The surface layout of Ni/Fe-P(δ−) covalent bonds on the one hand enriches the active sites for photocatalytic hydrogen evolution and opens up the valve for accelerated hydrogen production. On the other hand, it opens the migration channel for photogenerated electrons, which broadens the electron supply for photocatalytic hydrogen generation. FTIR spectroscopy and XPS results showed that Ni/Fe-P covalent bonds were successfully deployed on the catalysts. PL results showed that the introduction of covalent bonds had a facilitating effect on promoting the separation and migration of photogenerated electrons. The design of Ni-P(δ−) and Fe-P(δ−) bonds was further confirmed by In situ irradiated X-ray Photoelectron Spectroscopy to open the channels for trapping and transporting electrons. Based on the experimental results, we propose a possible bimolecular mechanism for synergistic hydrogen evolution, which provides novel and unique insights into the in-depth analysis of the influence of surface bonding states on the photocatalytic mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel green chemical mechanical polishing was developed. • Surface roughness Sa of 0.179 nm is achieved. • Chemical mechanical polishing mechanism is elucidated. Traditional chemical mechanical polishing (CMP) normally employs noxious slurries, leading to pollution to the environment. It is a challenge to achieve atomic surfaces of nickel (Ni) alloy using green CMP. To overcome this challenge, a novel green CMP was developed, including composite abrasives of ceria and silica, mandelic acid, hydrogen peroxide and deionized water. Using the developed green CMP, atomic surface with surface roughness Sa of 0.179 nm was achieved, under a scanning area of 50 × 50 μm2. Electrochemical tests indicate that the developed slurry has effective corrosion ability on Ni alloy. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy reveal that the Ni alloy was oxidized by hydrogen peroxide, forming oxides of Ni, chromium (Cr) and molybdenum (Mo). Cr and Mo oxides demonstrated better stability in mandelic acid, while Ni oxides reacted with hydrogen ions and produced Ni2+ and Ni3+ ions. The ions chelated with mandelic acid. Finally, the generated oxides and reaction products were removed by abrasives and a polishing pad under chemical and mechanical balanced functions. The developed green CMP paves a new avenue to obtain atomic surface of a Ni alloy for the possible applications of high-performance components in aerospace industry. [ABSTRACT FROM AUTHOR]

RuV-Co(OH) 2 was fabricated by the mild hydrothermal method of sacrificing ZIF-67 to codope vanadium (V) and ruthenium (Ru). RuV-Co(OH) 2 possessed excellent electrocatalytic activity toward hydrogen evolution reaction and glucose oxidation reaction. It was used as a bifunctional electrocatalyst for glucose-assisted hybrid water splitting to achieve high-efficiency hydrogen production. [Display omitted] • Hollow RuV-Co(OH) 2 arrays were prepared by simple two-step method. • Na 3 VO 4 was the key to the formation of hollow structure and Co(OH) 2 phase. • Codoping of V and Ru increased the electrocatalytical activity of RuV-Co(OH) 2 toward HER and GOR. • RuV-Co(OH) 2 was successfully used for glucose assisted hybrid water splitting. Electrochemical water splitting is a promising method for hydrogen production but is restricted by sluggish oxygen evolution reaction (OER), so we propose to replace OER with the thermodynamically preferred glucose oxidation reaction (GOR) to reduce the supply voltage. Herein, hollow RuV-Co(OH) 2 arrays have been fabricated by the hydrothermal method of sacrificing ZIF-67 to codope vanadium (V) and ruthenium (Ru). Electrochemical studies show that RuV-Co(OH) 2 has excellent hydrogen evolution reaction (HER) activity with a low overpotential of 77 mV at the current density of 10 mA cm−2 (η 10 = 77 mV) and good GOR activity. Density functional theory (DFT) calculations indicate that V and Ru tune the electronic structure of RuV-Co(OH) 2 , greatly increasing the density of the active sites. Moreover, RuV-Co(OH) 2 assembled glucose-assisted hydrogen evolution cell exhibits a battery voltage of 1.42 V for a current density of 10 mA cm−2, a significant reduction of 240 mV compared to overall water splitting along with higher-value glucose oxidation products. Furthermore, RuV-Co(OH) 2 exhibits outstanding stability. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate that RuV-Co(OH) 2 has superior mechanical stability. This work opens up a new approach to designing novel bifunctional electrocatalysts for energy-saving H 2 production and valuable coproductions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The NLA treatment prevents undesired dopant-diffusion and removes defects induced by ion-implantation in the near-surface region, effectively achieving highly active B concentration over approximately 1021 cm−3. • Using XPS, new chemical bonding states related to Si-B and Ge-B bonds in the near-surface region were identified in XPS Si 2 p and Ge 3 d spectra, which show the substitutionality of B-atoms upon NLA process. • Based on the depth profiles of the B 1 s peaks from the surface to melted depth, the relative ratios of active state in the NLA-treated films were confirmed and compared with the electrical activation rate measured by Hall measurements. Given that transistor dimensions are approaching atomic scale in metal–oxide–semiconductor field-effect-transistors (MOSFETs), attaining low-contact resistivity (ρ c) between contact-metal and Si is a primary challenge for source/drain (S/D) fabrications. To reduce ρ c , it is necessary to increase active dopant concentration in the semiconductor region underneath the contact-metal. High-dose ion-implantation and nanosecond laser-annealing (NLA) have been intensively investigated to produce highly activated layers in S/D regions. Particularly for the B-doped SiGe layers, which are used as S/D stressor for p-MOSFETs, non-substitutional B species are generated in the highly doped films at concentrations exceeding ∼ 1021 cm−3. These non-substitutional B are electrically non-activated and thus should be minimized to reduce ρ c. In this study, we investigated the chemical states and electrical activation in highly B-doped SiGe layer. Using X-ray photoelectron spectroscopy (XPS), we examined the substitutionality of B-atoms and identified new chemical states of Si-B and Ge-B bonds in Si 2 p and Ge 3 d peaks. In the B 1 s spectra, electrical activation states are determined by quantifying relative area ratios of the active/inactive B peaks, which are well matched with activation rates calculated by Hall measurements. Our findings systematically explained the activation behavior of NLA-treated B-doped SiGe films in high B-concentration ranges. [ABSTRACT FROM AUTHOR]

[Display omitted] • C(sp3) to C(sp2) relaxation depends on ion dose and annealing temperature. • Nitrogen exists mainly in C–N/C N bonding configuration below critical dose. • Ion retention probability decreases for higher doses due to recombination-assisted desorption. • Nitrogen desorption onset increases with ion dose. The properties of ultra-shallow nitrogen layers (<1 nm thick) in diamonds produced by very low energy (200 eV) N 2 + implantation in polycrystalline diamond films at different doses (1.25×1014, 3.50×1014, 7.85×1014, 1.30×1015 and 9×1015 ions·cm−2), followed by thermal annealing, are investigated by in situ X-ray photoelectron spectroscopy. Spectral analyses of C(1s) and N(1s) peaks reveal that a chemical effect occurs depending on nitrogen local concentration and annealing temperature. Nitrogen exists in a predominant C N/C–N bonding configuration, followed by minor contributions of C≡N and quaternary-N configurations. Annealing (300–1000 °C) imparts complex effects that depend on local nitrogen concentration and bonding. The onset of nitrogen thermal desorption increases with ion dose: 300 °C for 1.25×1014 and 3.50×1014, 400 °C for 7.85×1014, and ∼650 °C for 1.30×1015 and 9×1015 ions·cm−2. Upon annealing to 1000 °C, the remaining nitrogen concentration in the diamond subsurface region increases with ion dose. The C N/C–N configuration was more thermally stable than the C≡N, while the quaternary-N is constant with annealing temperature. The nitrogen ion retention probability increased for 1.25×1014 and 3.50×1014 and decreased for the higher doses due to recombination-assisted desorption. This study may have important implications for stabilizing near-surface NV- centers for quantum sensing applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface graphitization of diamond is achieved through thermal annealing. • Graphite/diamond pattern is selectively etched by hydroxide ion treatments. • The structure transformation is investigated via AFM, XPS, Raman and TEM. • The specific contact resistance is obtained by TML model. Ohmic contacts with low specific contact resistance are necessary for fabrication of diamond electronic devices. This work reports that graphite/diamond ohmic contacts can be obtained by thermal annealing of diamond, patterned by hydroxide ion treatment. Surface graphitization of diamond is achieved through rapid thermal annealing at 1050 °C in vacuum. The thickness of graphite layer is found to be dependent on the duration of annealing with an approximate rate of 3.3 ∼ 3.6 nm/minute. The alteration in surface structure is analyzed using Raman spectra, showing a continuously enhanced G peak with increasing annealing time. Early stages of graphitization are discovered by X-ray photoelectron spectroscopy, after annealing diamond samples for merely 0.5 ∼ 2 min. Additionally, a distinct atomic interface between graphite and diamond is observed via cross-sectional transmission electron microscopy. Further, the surface graphite is selectively etched by hydroxide ion treatments, protected by gold patterns. In the end, the specific contact resistance of the graphite/diamond contact is determined to be 2.53 × 10-4 Ω cm2 employing the transmission line model. [ABSTRACT FROM AUTHOR]

[Display omitted] • W/Si X-ray supermirror has been designed by block method and fabricated by IBS technique. • Improvement of X-ray optical property of W/Si periodic multilayer has been found by applying C buffer layer. • XPS measurement reveals drastic variation of chemical nature of interface when C buffer layer is applied. • High energy X-ray reflectivity of 36-layer W/Si supermirror also shows improvement using C buffer layer. • TEM measurement of supermirror confirms reduction of interface diffusion. The high energy spectral properties of X-ray supermirrors are governed mainly by the interface diffusion and compound formation at the interfaces. Using ion beam sputtering technique, a set of W/Si periodic multilayers with C buffer layer (BL) and without C BL have been prepared and the effect of BL has been studied by grazing incidence specular X-ray reflectivity, diffused X-ray scattering and X-ray photoelectron spectroscopy. Using C BL at the W-on-Si interfaces, reduction of interface diffusion and minimization of WSi x formation at the interfaces has been observed though signature of carbide formation has been noticed. Using the results an interface diffusion model has been proposed explaining the effect of C BL. Block method of X-ray supermirror design has been effectively used for reducing the number of layers of W/Si supermirror targeting the improvement of the performance. Finally, 36-layer W/Si supermirror with C BL and without C BL have been fabricated and the performance evaluated by reflectivity measurement using 25 keV synchrotron X-rays and cross sectional TEM measurements. This study has both technological implication in X-ray optical devices and also offers atomistic insight into the mechanism of improvement of the interface quality by application of ultra-thin buffer layer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen-defected WO 3 -OVs@Bi 2 MoO 6 S-scheme micro flowers heterojunction was designed. • S-scheme heterojunction and surface oxygen vacancies engineering promoted the interfacial charge transfer and separation. • The synergetic photocatalytic redox mechanism was revealed by theoretical calculations. The synergy between surface oxygen vacancies (OVs) and heterojunction engineering holds promising potential for substantially enhancing photoelectric conversion efficiency through the optimization of photogenerated charge carrier transport. Herein, novel WO 3 -OVs@Bi 2 MoO 6 S-scheme heterostructures are synthesized via a simple route for degradation of tetracycline hydrochloride (TC) using visible light. The S-scheme charge transfer mode markedly enhances the spatial separation and preservation of high-energy electrons/holes on Bi 2 MoO 6 (reduction) and WO 3 -OVs (oxidation), consequently providing WO 3 -OVs@Bi 2 MoO 6 photocatalysts with an improved redox capability. The optimal WO 3 -OVs@Bi 2 MoO 6 heterojunction demonstrates enhanced visible-light-driven photocatalytic degradation of tetracycline, exhibiting 4.86-fold and 4.17-fold higher efficiency compared to WO 3 -OVs and Bi 2 MoO 6 , respectively, with superior stability and reusability. Confirmation of the existence of the S-scheme charge transfer mechanism and oxygen vacancies (OVs) is achieved through a combination of density functional theory (DFT) calculations and in-situ X-ray photoelectron spectroscopy (XPS), substantiating the enhancement of charge separation and redox capability. Specifically, the presence of oxygen vacancies (OVs) on the surface of WO 3 nanofibers results in a reduction of the band gap energy due to the defect levels, consequently promoting increased electron conduction. Furthermore, the abundance of oxygen vacancies (OVs) expands the photo response range and facilitates charge transfer at the interface. This research opens new avenues for the successful photocatalytic degradation of tetracycline (TC) by integrating hierarchical S-scheme heterojunction design and cutting-edge defect engineering in photocatalytic heterojunctions. [ABSTRACT FROM AUTHOR]