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Herein, we report epitaxial growth of p-type Ni doped gallium chromium oxide thin film on Al2O3 substrates and studied its band alignment properties with that of the substrate. Thin films are grown using the magnetron-sputtering technique. Synchrotron-based XRD measurements, performed in the coplanar and non-coplanar geometries, confirm high-quality single domain epitaxial growth of p-type α-GaCrO3:Ni. Pendellosung oscillations around the Bragg peak and transmission electron microscopy reveal the high interfacial quality of p-type α-GaCrO3:Ni films with the substrate. Thin film, thickness ∼200 nm, shows around 70% average transmission. The values of valence band and conduction band offsets are determined to be 2.79 ± 0.2 and 0.51 ± 0.2 eV, respectively, which confirm straddling gap band alignment at the heterojunction. This type of alignment creates a threshold barrier for the selective charge carriers and is useful in enhancing the performance of a wide range of devices, including UV photodetectors, metal oxide semiconductor high electron mobility transistors, and light emitters. [ABSTRACT FROM AUTHOR]

Zinc ferrite (ZF) nanomaterials were synthesised by the sol–gel auto-combustion method. Synchrotron-XRD confirms the formation of the pure F-d3m spinel structure whereas EDX reveals the composition of synthesised nano ZF. We investigated and compared the dielectric properties of un-irradiated pellet ZF-UI and irradiated pellets ZF-I1 (pulsed Nd:YAG laser dose of 1.2 W, λ = 1064 nm), ZF-I2 (pulsed Nd:YAG laser dose of 1.5 W, λ = 532 nm) and ZF-I3 (continuous AlGaAs diode laser of 4 W, λ = 808 nm) at room temperature. Dielectric constant (ε′) decreased prominently for ZF-UI while it decreased gradually for ZF-I1 and its decrement for ZF-I2 and ZF-I3 is very slow whereas dielectric constant (ε″) decreased prominently for ZF-UI and ZF-I1while reduced slowly for ZF-I2 and ZF-I3 in the low-frequency region. ε′ becomes ∼69% for ZF-I1 and ∼9% for ZF-I2 and ZF-I3 at a higher frequency of 2 MHz whereas ε″ for radiated samples becomes steady and nearly equitable at higher frequencies in comparison to that of ZF-UI in the measured frequency range of 10 kHz to 2 MHz. Dielectric loss (tan δ) of all irradiated samples has decreased and become ∼33% for ZF-I3, 43% for ZF-I2, nearly equal for ZF-I1 at 104 Hz and then decreased continuously up to 2 MHz when compared to tan δ for ZF-UI. The Jonscher power law has been fitted in measured ac conductivity (σac) with angular frequency (ω) graphs. DC conductivity (σdc), temperature-dependent parameter B(T) and frequency exponent (n) have been extracted. σdc for all irradiated samples has decreased and become nearly 51% for ZF-I1, 3% for ZF-I2 and 2% for ZF-I3 in comparison to that of ZF-UI whereas B(T) increased to 1.6 times for ZF-I3 and decreased to 0.7 times for ZF-I1 and 0.2 times for ZF-I2 while n shows slight decrement for ZF-I2 and ZF-I3. Interpretation from Cole–Cole plots for un-irradiated and irradiated pellets is in agreement with our investigations. These results suggest that the dielectric properties of ZF can be controlled and tuned by laser irradiation. [ABSTRACT FROM AUTHOR]

Detailed structural and optical properties of α-(AlxCr1−x)2O3 (0 ≤ x ≤ 1) synthesized by the solid state reaction method have been investigated. Single phase α-(AlxCr1−x)2O3 with space group R 3 ¯ c is obtained for the full composition range of 0 ≤ x ≤ 1. Variations in the lattice parameters a and c have been determined. Lattice parameter c follows Vegard's law, while the lattice parameter a shows a clear deviation with a bowing parameter of −0.035 Å. This behavior of the lattice parameters of α-(AlxCr1−x)2O3 with x is explained in detail by studying the local structure. Extended x-ray absorption fine structure spectroscopy shows a reduction in the values of Cr–O bond lengths with composition x. Optical absorption measurements of α-(Al1−xCrx)2O3 for 0 ≤ x ≤ 1 show a large bandgap tunability of 1.9 eV (from 3.4 eV to 5.3 eV). The photoemission spectroscopy data and the analysis of partial density of states obtained from first principles electronic structure calculations suggest that the valence band maxima is mainly composed of Cr 3d levels, which hybridize with the O 2p levels. Increased contribution of O 2p partial density of states is observed with Al substitution, which is expected to enhance p-type carrier conduction in the α-(AlxCr1−x)2O3 system as compared to the parent α-Cr2O3 system. Thus, the large bandgap, its tunability in the UV region, and the predicted enhancement of p-type conductivity in the α-(AlxCr1−x)2O3 system make it a potential candidate for application in UV based photo-detectors and transparent electronics. [ABSTRACT FROM AUTHOR]

The effects of electric field and temperature on structural, dielectric, and ferroelectric properties of (1 – x)(Na0.50Bi0.50TiO3)-xAgTaO3 (x = 0, 0.03, 0.05, and 0.10) ceramics prepared via the modified sol-gel method were investigated. Rietveld refinement of synchrotron radiation x-ray diffraction data (SRPXRD) confirmed the rhombohedral (R3c) phase in all the unpoled samples. After poling, the samples remained in the rhombohedral phase for x ≤ 0.03, whereas for x ≥ 0.05, it showed a mixed rhombohedral and tetragonal (P4bm) phase. The anti-phase octahedral tilt angle was found to increase from 8.49° to 9.50° (for x = 0) and from 7.60° to 7.85° (for x = 0.10) with poling due to the long-range ordering phenomenon in the lattice system. The temperature-dependent dielectric study showed that the depolarization temperature decreases with increasing composition. Unpoled x = 0.10 composition exhibited the wide thermal stability dielectric constant in the temperature range 120-450 °C with 1795 ± 15% (tan δ < 0.041). Polarization versus electric field measurement revealed that at room temperature, the presence of anti-ferroelectric ordering increases the energy storage efficiency from 2.6% (for x = 0) to 48.2% (for x = 0.10). With increasing temperature, it increased from 48.2% (30 °C) to 85.5% (140 °C) for x = 0.10 composition. Improvement in the energy storage efficiency was correlated with structural changes probed by temperature dependent SRPXRD measurements; it confirmed the increase in antiferroelectric ordering with increasing temperature. Dielectric and ferroelectric results indicate the usefulness of this material system in the field of wide thermal stability dielectric constant and high-temperature energy storage applications. [ABSTRACT FROM AUTHOR]

A detailed study was carried out to investigate the effects of poling on structure, vibrational, dielectric, and ferroelectric properties of donor-doped (V5+ at Ti4+-site) lead-free Na0.47Bi0.47Ba0.06Ti(1-x)VxO3, (x =0, 0.01, and 0.03) ceramics fabricated via a modified sol-gel method. Rietveld refinement of synchrotron radiation source powder x-ray diffraction data showed that unpoled samples are in rhombohedral R3c phase whereas poled samples showed a mix rhombohedral R3c and tetragonal P4mm phases at ambient temperature, due to a long-range order established in lattice system after poling. V+5 doping increases the rhombohedral distortion in unpoled and poled samples while it reduces the tetragonality in poled samples. Vibrational study revealed that unpoled samples have more lattice disorder compared to poled samples. X-ray absorption near edge spectroscopy measurement confirmed that Ti and V are in 4+ and 5+ oxidation states, respectively, for all poled and unpoled samples. The average grain size was found to decrease from 5.6 ± 0.5 μm for x =0 to 1.0 ± 0.2 μm for x =0.03. Depolarization temperature was found to increase significantly in poled samples from ∼104 °C for undoped sample to 150 °C for the sample with 1% vanadium substitution. Drastic improvements in ferroelectric and dielectric properties are explained in terms of structural changes. High remnant polarization Pr ∼ 31.4 μC/cm2 and moderately low coercive field Ec ∼ 20 kV/cm have been observed at an applied electric field of ∼35 kV/cm for the sample with 1% vanadium substitution which makes it an attractive candidate for ferroelectric applications. [ABSTRACT FROM AUTHOR]

High-quality, continuous transition-metal dichalcogenide (TMD) thin films with large-area coverage are the prerequisites for practical device applications. To address the growing demand, here we report high photoresponse and high detectivity of WS2 nanosheet/Si p–n heterojunction diodes for potential application in UV–visible broadband photodetection based on the wafer-scale deposition of WS2 nanosheets. Monolayer equivalent efficiency, i.e., high responsivity and high detectivity, has been achieved in these devices utilizing its nanotextured morphology. Nanotexturization in the surface morphology increased the effective area for absorption as well as contributed to quantization, leading to superior device performance. RF sputtering followed by high-temperature annealing in the sulfur-rich environment has been adopted to achieve stoichiometric WS2 films with high crystalline quality. The valence band offset for the WS2/Si heterointerface has been determined to be 0.48 ± 0.2 eV, for the band alignment of heterojunction devices. The fabricated n-WS2/p-Si junction diode displayed excellent rectifying characteristics (rectification ratio of ∼630) with a low leakage current (∼1 × 10–7 A). The photodiode exhibits a superior photo-to-dark current ratio (∼1200) and very high photoresponsivity (>4 A/W) under the reverse bias condition. Moreover, a high detectivity of ∼4.8 × 1012 Jones with a linear dynamic range (LDR) of 62 dB at −3 V has also been achieved. A reasonably fast response time, of approximately a few milliseconds of the fabricated photodiode, has made them excellent candidates for large-area photodetectors, operational for the broadband spectral range (300–800 nm). [ABSTRACT FROM AUTHOR]

In this study, the rhombohedral crystalline pure phase BiFeO3 (BFO) of irregularly shaped spherical particles of ≈100 nm and energy bandgap of ≈2.31 eV are synthesized by sol–gel auto‐combustion method and explored as electrode material for photo‐assisted supercapacitor. The electronic structure studies revealed that the coexistence of heterovalent Bi and Fe elements accelerated the electrochemical redox kinetics and photo‐assisted charge storage properties. The resonant photoemission studies confirmed that near the Fermi level, the valence band spectra comprised the Fe3d and O2p hybridized states. The Fe‐O hybridized state felicitates the charge transfer transitions (O2p (h+) + hυ ↔ Fe3+ + e− ↔ Fe2+), which assists the intercalation/de‐intercalation process of OH− anions. Therefore, BFO has delivered 26.77% photo efficiency and the enhanced specific capacity of 21 Cg−1 at 2 Ag−1 in aq. 3m KOH under illumination, which is attributed to the accelerated photo‐generated charge carrier separation and storage with surface polarization effect. BFO also delivered capacitance retention of 77.5% even after 1000 continuous GCD cycles under visible light irradiation. [ABSTRACT FROM AUTHOR]

Crystalline ZnFe2O4 (zinc ferrite) material was prepared using the sol–gel technique and converted in the forms of 3 pellets, out of which 2 pellets were irradiated at room temperature by pulsed Nd:YAG laser with 1.5 W, λ = 532 nm named ZF1 and continuous AlGaAs diode laser of 4 W, λ = 808 nm called ZF2, respectively, while the 3rd pellet was kept as control and named ZF. Synchrotron X-ray Diffraction (S-XRD) reveals the marginal variation in the structure having the lattice parameters of 8.4364 Å for ZF, 8.4176 Å for ZF1 and 8.4187 Å for ZF2. The porosity after laser irradiation has been increased to 10.87% for ZF1 and 10.84%, for ZF2 from 10.28% for ZF. The blocking temperature (TB) has been ∼15 K for all samples. There had been a slight variation in the magnetization of irradiated pellets at 5 and 300 K compared to ZF. The separation between ZFC and FC curves, the measure of interaction between Fe ions has increased for irradiated pellets when compared with the separation for ZF. Moreover, magnetization (M) versus applied magnetic field (H) at 5 K in the range of ±1 T shows the ferrimagnetic behaviour and this ordering has been seen up to TB as visible from M-T curves, whereas the material becomes superparamagnetic above TB as observed from M-T & M-H measurements. [ABSTRACT FROM AUTHOR]

The development of a metallic copper-based catalyst system remains a significant challenge. Herein, we report the synthesis of highly stable, active, and reusable Cu 0 catalyst for the carboboration of alkynes using carbon electrophiles and bis(pinacolato)diboron (B 2 pin 2 ) as chemical feedstocks to afford di- and trisubstituted vinylboronate esters in a regio- and stereoselective manner with appreciable turnover number (TON) of up to 2535 under mild reaction conditions. This three-component coupling reaction works well with a variety of substituted electrophiles and alkynes with broad functional group tolerance. In addition, a wide range of terminal and challenging internal alkynes were efficiently converted into hydroborated products in up to >99 % yield with excellent regioselectivity in the absence of carbon electrophiles. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) analysis confirm that the oxidation state of the copper in the catalyst is zero. The broad range of organic transformations, effectiveness, and recyclability of this Cu 0 catalyst are the major achievements that provide an environmentally friendly route for the efficient production of tri- and tetrasubstituted olefins, key intermediates in organic synthesis. The gram-scale reaction and synthetic transformations further highlights the usefulness of these methods., (© 2025 Wiley-VCH GmbH.)

Ti 3 C 2 -X MXenes have attracted tremendous research interest because their 2D laminar morphology provides numerous functional applications. The application options rely on the purity and interlayer spacing of MXenes, which eventually depend on the purity of the MAX phase. This motivated us to synthesize pure MAX phases to produce MXenes at large scale using simpler and less expensive techniques. However, producing prerequisite pure MAX phases at atmospheric pressure and relatively lower temperatures is still a challenging task. This study reports the synthesis of thermally stable pure MAX phases (and MXenes) by systematically varying the molar ratio of the precursors, reaction temperature, and reaction time using a novel MS 5 process under atmospheric pressure conditions. The purity of MAX phases under different synthesis conditions shows a direct interrelationship with the 2D laminar morphology of MXenes. The highest purity of >99% for the MAX phase was achieved by reacting Ti : Al : C precursors in a 3 : 1.5 : 1.9 molar ratio at 1350 °C for 90 min and delivered highly distinctive 2D nanostructured laminar MXenes with larger interlayer spacing and specific surface area ( i.e. , 8.8 ± 0.1 m 2 g -1 ), which are superior to those in previously reported works. These results reveal that the precursor molar ratios and reaction conditions tailor the MAX phase purity, thereupon, they are crucial for achieving good quality 2D laminar MXenes with large specific surface areas, further enhancing the performance of MXene-related devices. The developed MS 5 -MXenes, when probed as electrodes for Na ion applications, show excellent initial and reversible capacity values of 142 mA h g -1 and 103 mA h g -1 (at 50 mA g -1 ), respectively.

Multifunctional photodetectors (PDs) with broadband responsivity ( R ) and specific detectivity ( D *) at low light intensities are gaining significant attention. Thus, we report a bilayer PD creatively fabricated by layering two-dimensional (2D) Sb 2 Se 3 nanoflakes (NFs) on one-dimensional (1D) ZnO nanorods (NRs) using simple thermal transfer and hydrothermal processes. The unique coupling of these two layers of materials in a nanostructured form, such as 2D-Sb 2 Se 3 NFs/1D-ZnO NRs, provides an effective large surface area, robust charge transport paths, and light-trapping effects that enhance light harvesting. Furthermore, the combination of both layers can effectively facilitate photoactivity owing to proper band alignment. The as-fabricated device demonstrated superior overall performance in terms of a suitable bandwidth, good R , and high D * under low-intensity light, unlike the single-layered 1D-ZnO NRs and 2D-Sb 2 Se 3 NF structures alone, which had poor detectivity or response in the measured spectral range. The PD demonstrated a spectral photoresponse ranging from ultraviolet (UV) to visible (220-628 nm) light at intensities as low as 0.15 mW·cm -2 . The PD yielded a D * value of 3.15 × 10 13 Jones (220 nm), which reached up to 5.95 × 10 13 Jones in the visible light region (628 nm) at a 3 V bias. This study demonstrated that the 2D-Sb 2 Se 3 NFs/1D-ZnO NRs PD has excellent potential for low-intensity light detection with a broad bandwidth, which is useful for signal communications and optoelectronic systems.