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Hydrogen trapping is one of the factors leading to hydrogen embrittlement in heat-treatable high-strength aluminum alloys. The effect of coherency of precipitates on the corrosion-induced hydrogen trapping in aluminum alloy 2024 was investigated by performing artificial aging treatments before corrosion exposure. Two aging temperatures were employed, 170 and 210 °C, for aging times spanning the underaged, peak-aged and overaged conditions. Hydrogen uptake was induced by exfoliation corrosion. Hydrogen evolution from trapping sites was followed by thermal desorption spectroscopy. High resolution transmission electron microscopy combined with geometric phase analysis was performed to analyze the coherency of the precipitates. The results indicated that the coherency state between precipitates and the matrix plays an important role in hydrogen trapping. Hydrogen evolving at 300 °C (T2 state) corresponds to hydrogen trapped by the stress fields of coherent GPB zones and S΄΄ (Al10Cu3Mg3) phases, which form at aging temperatures, below the corresponding solvus temperature.

Capacitive deionization (CDI) is a relatively new technique that uses electric double layers (EDLs) effects, high affinity chemical groups, redox-active materials, and membranes capacitive electrosorption principle for the desalination. In this paper, hydrothermal synthesis of CFO metal oxide NPs coupled with the vacuum filtration method, or the freeze-drying method is used to fabricate high-performance nanocomposite: CFO-Graphene, CFO-CNTs, and CFO-3DrGO. Two times of hydrothermal reaction methods were conducted to fabricate the CFO-3DrGO Nanoengineered as a pseudocapacitive/EDL electrode. The results have demonstrated that the SAC of CFO–3DrGO/CFO (64.5 mg g− 1) is greater than that of the CFO–graphene/CFO (55.16 mg g− 1) and CFO–CNTs/CFO (21.5 mg g− 1) due to the better surface area of the CFO–3DrGO nanocomposite (330 m2 g− 1). The higher surface area of the CFO–3DrGO is due to the porous and interconnected 3D structure of the 3DrGO, and it provides a larger surface area to form EDL capacitance. In addition, the added porous 3DrGO entangled with the spinel crystals (CoFe2O4) in the composite allowed for a quick ion diffusion across the interconnected open macroporous structures.

In this work, we study and characterize the layout-induced device strain and its impact on RF performance of 22-nm-ultrathin body and buried oxide fully depleted silicon-on-insulator (UTBB FDSOI) P-channel field-effect transistor (PFET). This will help in boosting and optimizing the RF performance for the targeted application. With shrinking device dimensions, conventional stress liners and embedded stressors used in strain-engineered CMOS devices become less effective. Therefore, intrinsically strained materials, such as compressively strained SiGe, are widely used to boost the holes’ mobility in the channel. The stress level depends on both the manufacturing process and device geometry, and the optimization of these leads to improved dc and RF performances of PFET devices. We hereby study various layout parameters, such as width and length of the active region, contacted poly pitch, number of fingers, and source/drain contact, to maximize the channel uniaxial strain parallel to the current flow direction and, thus, improve the electrical performances. The studied layout parameters are then applied on sliced-active (RX) structures, which enables to achieve up to 30% improvement of both ${f}_{T}$ and ${f}_{\text {MAX}}$ parameters of SiGe PFET with respect to a reference device. This also allows reducing the parasitic capacitance without significantly degrading the dc performance. The device strain modeling and physical characterization were conducted through the finite-element method (FEM) and nanobeam electron diffraction (NBED) in the transmission electron microscopy (TEM), respectively.

2D Molybdenum disulfide (MoS2) nanoplatelets were synthesized via a green bottom-up strategy using non-toxic l -Cysteine as sulfur source. The hydrophobic MoS2 nanoplatelets assisted by hydrophilic 3-(3, 4-dihydroxyphenyl)-l-alanine ( l -DOPA) were coated on a thin film composite nanofiltration (TFC-NFG) membrane. The accelerated fouling experiments were conducted by using bovine serum albumin (BSA) as model organic foulant, and MoS2 coated membrane demonstrated excellent resistance with almost no flux decline within first hour of filtration, whereas the uncoated membrane showed flux decline immediately from the beginning of the experiment. After 5-hour filtration, the flux reduced by only 26% for MoS2 coated membrane with a higher flux recovery rate of 85.4% after washing by de-ionized (DI) water, whereas 45% flux decline was observed for uncoated membrane with lower flux recovery of 68%. These antifouling effects attributed by MoS2 coated membrane were underpinned by combined unique interfacial properties offered by 2D tri-atomic layered MoS2 morphology including dispersive surface tension, reduced surface roughness, weaker MoS2-foulant interactive forces, and negatively charged surface. This research positively confirms the role of 2D MoS2 nanoplatelets as an anti-fouling coating on membranes and brings up more possibility for applying other nanomaterials in 2D family in water applications such as desalination and water treatment.

This work provides useful insights into the development of HfO2-based memristive systems with a p-type silicon bottom electrode that are compatible with the complementary metal–oxide–semiconductor technology. The results obtained reveal the importance of the top electrode selection to achieve unique device characteristics. The Ag/HfO2/Si devices have exhibited a larger memory window and self-compliance characteristics. On the other hand, the Au/HfO2/Si devices have displayed substantial cycle-to-cycle variation in the ON-state conductance. These device characteristics can be used as an indicator for the design of resistive-switching devices in various scenes such as, memory, security, and sensing. The current–voltage (I–V) characteristics of Ag/HfO2/Si and Au/HfO2/Si devices under positive and negative bias conditions have provided valuable information on the ON and OFF states of the devices and the underlying resistive switching mechanisms. Repeatable, low-power, and forming-free bipolar resistive switching is obtained with both device structures, with the Au/HfO2/Si devices displaying a poorer device-to-device reproducibility. Furthermore, the Au/HfO2/Si devices have exhibited N-type negative differential resistance (NDR), suggesting Joule-heating activated migration of oxygen vacancies to be responsible for the SET process in the unstable unipolar mode.

A compact, ultra-broadband and high-performance silicon TE-pass polarizer is proposed and demonstrated experimentally. It is based on partially-etched (ridge) waveguide adiabatic S-bends, input/output tapers and side gratings on a silicon-on-insulator (SOI) platform. A compact footprint and weak back reflections are obtained due to the bent waveguide and the tapers, respectively. An extremely high extinction ratio is achieved by scattering the undesired light in the slab section using the side gratings. The 3D FDTD simulations show a TE loss less than 0.3 dB and an extinction ratio greater than 30 dB over a 500 nm wavelength range (1200 nm to 1700 nm). Measured results show a high TM loss (> 35 dB) and a low TE insertion loss (< 1.5 dB), over a 200 nm wavelength range (1450 nm to 1650 nm). The measured TE loss is < 0.6 dB at a communication wavelength of 1550 nm. The footprint of the optimized design is 65 µm × 20 µm.

Light-operated materials have gained significant attention for their potential technological importance. To achieve molecular motion within extended networks, stimuli-responsive units require free space. The majority of the so far reported 2D-extended organic networks with responsive moieties restrict their freedom of motion on account of their connectivity providing constrained free volume for efficient molecular motion. We report here a light-responsive azobenzene-functionalized covalent organic framework (TTA-AzoDFP) designed in a way that the pendent azobenzene groups are pointing toward the pore channels with sufficient free volume necessary for the unencumbered dynamic motion to occur inside the pores of the covalent organic framework (COF) and undergo a reversible trans-cis photoisomerization upon light irradiation. The resulting hydrophobic COF was used for the storage of rhodamine B and its controlled release in solution by the mechanical motion of the azobenzene units triggered by ultraviolet-light irradiation. The TTA-AzoDFP displayed unprecedented photoregulated fluorescence emission behavior upon UV-light irradiation. Size, emission, and degree of hydrophobicity with respect to trans-cis-trans photoisomerization could be reversibly controlled by alternating UV- and visible-light exposure. The results reported here demonstrate once again the importance of the careful design of the linkers not only to allow the incorporation of molecular switches within the chemical structure of COFs but also to provide the required free space for not hindering their motion. The results demonstrate that responsive COFs could be suitable platforms for delivery systems that can be controlled by external stimuli.

Capacitive deionization (CDI) has been used to remove salt ions with carbon electrodes by the electrical double layer (EDL) mechanism. Other non-carbon materials based on pseudocapacitive mechanism resulting from faradaic reactions with fast electrosorption/desorption properties have emerged as new promising electrode materials. Until now, pseudocapacitive behavior was limited to thin film electrodes with nanometer thickness and was not yet suitable for practical application. In this work, we employed a two-times of hydrothermal synthesis process constructing MnFe2O4/Porous rGO (MFO/PrGO) nanostructure as pseudocapacitive electrodes. In this carefully designed architecture, the dense structure of MFO/rGO prepared by first-time hydrothermal process provided good connections of MFO nanoparticle with rGO framework for efficient redox charge transfer; the chemically-etched porous rGO used in the second-time hydrothermal process offered hierarchical pores for easier access of the electrode materials, both contributed in enhanced pseudocapacitive electrosorption. HRTEM verified the MnFe2O4 spinel structure and measured the inter-planar lattice parameter which functioned for ion intercalating in and out of the electrode. The MFO/PrGO electrode resulted in 237 F/g in electrosorption of ions from aqueous solution which was higher than the MFO only electrode. Finally, in the CDI experiment, the great salt electrosorption capacity of 8.9 mg/g and 100% regeneration in multiple cycles were achieved by the MFO/PrGO nanocomposite electrode. These results paved the way for using spinel compounds and graphene nanocomposite electrodes for efficient electrosorption and desalination.

2D Molybdenum disulfide (MoS

We report on quantification and elastic strain mapping in two artificial [BaZrO3]xᴧ/[BaTiO3](1-x)ᴧ (BZxᴧ/BT(1-x)ᴧ) superlattices having periods of Λ = 6.6 nm and Λ = 11 nm respectively, grown on (0 0 1) SrTiO3 single crystal substrate by pulsed laser deposition technique. The methodology consists of a combination of high-resolution scanning transmission electron microscopy and nanobeam electron diffraction associated with dedicated algorithm for diffraction patterns processing originally developed for semiconductors to record the strains at atomic scale. Both in-plane and out-of-plane elastic strains were then determined at 2 nm spatial resolution and their average values were used to map the strains along and transverse to the epitaxial growth direction of both samples to determine its variation along several BZ/BT interfaces. In addition, the variation of the width of the inter-diffusion BT/BZ interfaces and intermixing between different layers are estimated. The obtained width average value measured in these inter-diffusion interfaces vary from 8 to 12% and from 9 to 11% for both superlattices having Λ = 6.6 nm and Λ = 11 nm respectively. These inter-diffusion interfaces and the inherent elastic strains due to the confined layers of the superlattices are known to be the most important parameters, responsible of the change in their functional properties.

We present the synthesis of a silver nanoparticle (AgNP) based drug-delivery system that achieves the simultaneous intracellular delivery of doxorubicin (Dox) and alendronate (Ald) and improves the anticancer therapeutic indices of both drugs. Water, under microwave irradiation, was used as the sole reducing agent in the size-controlled, bisphosphonate-mediated synthesis of stabilized AgNPs. AgNPs were coated with the bisphosphonate Ald, which templated nanoparticle formation and served as a site for drug attachment. The unreacted primary ammonium group of Ald remained free and was subsequently functionalized with either Rhodamine B (RhB), through amide formation, or Dox, through imine formation. The RhB-conjugated NPs (RhB–Ald@AgNPs) were studied in HeLa cell culture. Experiments involving the selective inhibition of cell membrane receptors were monitored by confocal fluorescence microscopy and established that macropinocytosis and clathrin-mediated endocytosis were the main mechanisms of cellular uptake. The imine linker of the Dox-modified nanoparticles (Dox–Ald@AgNPs) was exploited for acid-mediated intracellular release of Dox. We found that Dox–Ald@AgNPs had significantly greater anti-cancer activity in vitro than either Ald or Dox alone. Ald@AgNPs can accommodate the attachment of other drugs as well as targeting agents and therefore constitute a general platform for drug delivery.

In this work, the fouling resistance of TFC (thin film composite) nanofiltration membranes have been enhanced using an electrostatically coupled SiO

An amphiphilic Janus-like cellulose acetate-molybdenum disulfide (CA-MoS2) fibrous sponge has been designed and synthesized. It aimed to achieve efficient removal of fine oil droplets from industrial wastewater. The CA-MoS2 fibrous sponge featured an amphiphilic interfacial characteristic with oleophilic MoS2 nanospheres embedded in hydrophilic fibrous CA polymer networks. The hydrophilic CA allowed the sponge to be stable in the water, so helped the oleophilic MoS2 to reach the targeted oil droplets. Toluene was used as a model oil compound in experimental evaluations. It confirmed that the amphiphilic CA-MoS2 fibrous sponge demonstrated 99.9% of toluene removal from 1 v/v% of toluene in water emulsions with excellent regeneration and recycling ability. As high as 57.03 mg of toluene per gram of CA-MoS2 sponge was achieved within 15 min from 20 v/v/% of toluene in water emulsion. At pH of 8, CA-MoS2 sponge showed 100% of toluene removal exceeded that at the lower pH values. At 40°C, the adsorption value was 7.6% less than at lower temperature 25°C. In complementary of the experimental works, an artificial neural network (ANN) model was developed to predict toluene adsorption behavior, good agreement between experimental and predicted data was achieved with R2 = 0.999. These findings make amphiphilic Janus CA-MoS2 fibrous sponge a promising material for oil consisting industrial wastewater and municipal wastewater treatment and reuse. Developed ANN modeling approach provided an advantage for efficient adsorption predictions.

Moisture can modulate the resistive switching dynamics in oxide-based electrochemical metallization devices. Unconventional testing environments such as vacuum, could possibly shift the device characteristics, requiring therefore a careful investigation. This work investigates the write/erase behavior of Cu/HfO2(~80-nm-thick)/p+-Si devices in ambient atmosphere and vacuum, under similar electrical bias applied to the top Cu electrode. In vacuum (~5.3 × 10−3 Pa), a parasitic negative SET (N-SET) readily arises during the “erase” operation, unlike in ambient air. The electrical studies and physicochemical analyses of electrically-biased and pristine devices reveal that the “erase” process is sensitive to the environment. Vacuum facilitates the electric-field-controlled generation of an oxygen-vacancy-based path that likely induces a parasitic N-SET at the negative voltage. This path is aided by the presence of partially-ruptured copper filaments at the HfO2/p+-Si interface. The vacuum effects leading to the N-SET are eliminated by introducing a passivating gas environment (zero-air or nitrogen), or device encapsulation.

Vertically aligned MoS2 nanosheets (NSs) with exposed edges were successfully synthesized over a large area (∼2 cm2). The NSs were grown using an ambient pressure chemical vapor deposition technique via rapid sulfurization of sputter deposited thick molybdenum films. Extensive characterization of the grown MoS2 NSs has been carried out using high resolution scanning and transmission electron microscopy (SEM & TEM). A special care was given to the TEM lamella preparation process by means of a focused ion beam to preserve the NS growth direction. The cross-section TEM measurements revealed the growth of densely packed, vertically aligned and straight MoS2 NSs. Additional characterization techniques such as atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence (PL) were used to evaluate the MoS2 NSs. These studies revealed the high crystallinity and quality of the synthesized NSs. The MoS2 NSs show visible light emission similar to mechanically exfoliated monolayer MoS2 NSs. The striking PL signal comes from the exposed edges as shown by experimental and theoretical calculations. The vertical MoS2 NSs also exhibit a hydrophobic character with a contact angle of 114°. The as-grown MoS2 NSs would be highly useful in the development of catalysis, nano-optoelectronics, gas-sensing and bio-sensing device applications.

This work demonstrates the viability of direct fabrication utilizing a single (deposition/anneal) process for polycrystalline silicon germanium sub-micro particles. The process combines plasma chemical vapor deposition enhanced with inductively coupled radio frequency plasma at intermediate pressure and high temperature for deposition and rapid thermal annealing as a final step to tune the particles' growth. The deposition process utilizes high plasma density at low kinetic ion energy providing a relatively high deposition rate, favorable for industrial fabrication requirements. Our characterization was performed at two points in the process, post-deposition and post-annealing. Raman spectroscopy and X-ray diffraction were combined to determine the value of stoichiometry x and hence the nature of the obtained compound. Post-annealing, the samples were analyzed by atomic force microscopy, and scanning and transmission electron microscopy to investigate the crystallization, growth kinetics and the strain relaxation of the particles. Our findings show that optimized coarsening of the crystals occurred after annealing at 600 °C for 30 minutes which resulted in internal strain minimization while the composition stoichiometry is kept constant. In addition, the presence of well-defined geometrical facets observed on the surface of SiGe particles, as revealed by atomic force microscopy analyses, suggests that the SiGe particles seem to grow along a preferred crystallographic orientation.

The development of novel materials for removal of organic contaminants from water is of global importance for the preservation of the environment. Here, we describe the synthesis and characterization of the first porous covalent calix[4]arene-based polymer (CalP) and its use for water purification. CalP has a high surface area, large pore volume and excellent sorption capacity for a range of organic solvents, oils, and toxic dyes. The polymer can selectively absorb up to seven times its weight of oil from oil/water mixtures. From aqueous solutions, it can adsorb both anionic and cationic dyes in under 15 minutes. Its uptake capacity is significantly higher than those of the most adsorbent materials reported to date, including commercial activated carbon. Additionally, the polymer can be easily regenerated using mild washing procedures and reused several times with no loss of absorption efficiency.

The development of stimuli-responsive materials capable of transducing external stimuli into mechanical and physical changes has always been an intriguing challenge and an inspiration for scientists. Several stimuli-responsive gels have been developed and applied to biomimetic actuators or artificial muscles. Redox active actuators in which the mechanical motion is driven chemically or electrochemically have attracted much interest and their actuation mechanism is based on the change in electrostatic repulsion and the loss or gain of counterions to balance newly formed charges. Actuation can also be promoted by changing the hydration state of the material leading to the release/adsorption of water molecules from the network, inducing a direct shrinking/swelling of the material respectively. A cationic crystalline dynamic covalent gel was obtained via the formation of imine bonds between 2,6-diformyl pyridine and triamino guanidinium chloride. The gel exhibits a reversible contraction/expansion behavior in response to base (oxidation, –H+, –e–) and acid (reduction +H+, +e–) respectively. The oxidation induces a color change and contraction of the gel with a concomitant increase in its strength. As synthesized, the cationic gel is denser than water and sinks when placed in water. Upon oxidation, the radical cationic gel expels water molecules rendering it less dense than water and the gel is propelled to the surface without any loss of its structural integrity. These results demonstrate that a careful choice of amine and aldehyde linkers can give rise to imine-linked materials capable of tolerating and resisting extreme acidic and basic conditions while performing work.

Mesoporous iron-oxide nanoparticles (mNPs) were prepared by using a modified nanocasting approach with mesoporous carbon as a hard template. mNPs were first loaded with doxorubicin (Dox), an anticancer drug, and then coated with the thermosensitive polymer Pluronic F108 to prevent the leakage of Dox molecules from the pores that would otherwise occur under physiological conditions. The Dox-loaded, Pluronic F108-coated system (Dox@F108-mNPs) was stable at room temperature and physiological pH and released its Dox cargo slowly under acidic conditions or in a sudden burst with magnetic heating. No significant toxicity was observed in vitro when Dox@F108-mNPs were incubated with noncancerous cells, a result consistent with the minimal internalization of the particles that occurs with normal cells. On the other hand, the drug-loaded particles significantly reduced the viability of cervical cancer cells (HeLa, IC50 =0.70 μm), wild-type ovarian cancer cells (A2780, IC50 =0.50 μm) and Dox-resistant ovarian cancer cells (A2780/AD, IC50 =0.53 μm). In addition, the treatment of HeLa cells with both Dox@F108-mNPs and subsequent alternating magnetic-field-induced hyperthermia was significantly more effective at reducing cell viability than either Dox or Dox@F108-mNP treatment alone. Thus, Dox@F108-mNPs constitute a novel soft/hard hybrid nanocarrier system that is highly stable under physiological conditions, temperature-responsive, and has chemo- and thermotherapeutic modes of action.

Direct aged alloy 718 was subjected to isothermal and non-isothermal aging at temperatures above 650 °C to assess its potential use at higher temperatures. Non-isothermal aging conditions were achieved by thermal cycling to represent the operating conditions of aero-engine components. The effect of different aging treatments/conditions on mechanical properties was understood by performing Brinell hardness and hot tensile tests at 650 °C. Brinell hardness and hot tensile properties were found to decrease with increasing aging time and higher temperature. Additionally, age related mechanical properties degradation was found to accelerate after thermal cycling. According to High Resolution Transmission Electron Microscopy, all aged samples showed coarsening of γ′, γ″ and δ phases, in addition to the transformation of γ″ into ordered orthorhombic phase δ by ledge growing mechanism. This transformation, which was accelerated by thermal cycling is controlled by the orientation of γ″ and/or δ precipitates with respect to γ matrix and also by the diffusion of solute atoms assisted by dislocations at the precipitate-matrix interface. This study elucidates the mechanism of γ″ to δ transformation and suggests this mechanism is responsible for the accelerated loss of mechanical properties of alloy 718 under non-isothermal conditions. Keywords: Alloy 718, Thermal aging, Thermal cycling, HRTEM, Ledge growth mechanism

The immobilization of molecular switches within materials can give rise to new bulk properties that are useful for a variety of applications. Here, we report the synthesis and characterization of covalent organic polymers composed of cyclotriphosphazene core moieties linked together by redox-switchable viologen units. The polymers are isolated as non-porous, micro- and nano-sized spherical particles whose constituent viologens allow access to three distinct redox states: dicationic, radical-cationic and neutral. With viologens in their dicationic state, the particles were used for magic printing, gaseous ammonia sensing, and efficient oxoanion capture. With viologens in any oxidation state, the polymers were capable of capturing 200 to 380% of their weight of iodine vapor. Iodine capture within all of the viologen-based polymers was fast, requiring minutes, as compared to capture by previously reported polymers, which requires hours. With viologens in their neutral state, the polymers exhibited the highest iodine loadings reported to date. Upon one and two-electron reduction, the polymers partially or completely lost their cationic character and, concomitantly, their anion removal capability.

This study investigates the resistive switching (RS) behavior of Ag/HfO2(3 nm-thick)/SiO x (interfacial-layer)/Si devices. The findings are drawn from a systematic electrical and material characterization of the fabricated devices. Based on the current-time (I-t) and current-voltage (I-V) measurements, it is inferred that both metal and oxygen ion migration play a significant role in the switching events, leading to bipolar and unipolar switching modes depending on the biasing scheme. The results demonstrate two competing switching mechanisms taking place when the biasing voltage is increased beyond the RESET voltage in the bipolar mode. The devices are also shown to exhibit self-rectifying characteristics when the bias is applied to the Ag electrode. The proposed method of investigating the total charge passed through the device within the time to SET, during the I-t characterization, is particularly useful for identifying the current transport models governing the high-resistance state. The results reported in this manuscript provide useful insights into the control of RS behavior in this scientifically and technologically important material system. Developing a thorough understanding of the fundamental physics governing the observed RS behavior is a substantial step for the growing progress in the memristor device research, as well as for its potential exploitation in diverse CMOS-compatible applications.

Multiphase TiO2 was stably modified by vacuum treatment for a dramatic improvement in visible-light absorption and photocatalytic reactivity. The samples were made of rutile-brookite, bare or N dop ...

Hexagonal‐shaped nanoplates (HNPs) of MoS2 on vertically aligned carbon nanotubes (CNTs) over a patterned area (a circular area of 1 cm2 diameter) are produced by chemical vapor deposition technique. With an optimized initial Mo film thickness, a uniform coverage of MoS2 HNPs with a thickness around 20 nm is achieved. The results confirm that the CNT template plays an important role in the MoS2 HNPs growth. Each MoS2 HNP consists of abundant exposed edges, interesting for sensing and catalysis applications. High crystallinity and quality of the as‐produced material are revealed by X‐ray photoelectron and Raman spectroscopies. Furthermore, NO2 gas‐sensing studies show better sensitivity and recovery for MoS2/CNT samples as compared to pristine CNTs. The detection of NO2 gas in a few tens of parts per million to a few hundreds of parts per billion range, at room temperature, is achieved. Density‐functional theory calculation indicates that the exposed edges of MoS2 play a significant role in the NO2 sensing as compared to horizontally aligned MoS2 layers. The present report can promote the research toward the fabrication of efficient and reliable MoS2‐based hybrid materials for toxic gas‐sensing applications for air quality monitoring in various environments., This research leading to these results received funding in part from European Union Seventh Framework H2020 Program under Grant Agreement No. 696656 Graphene Flagship. J.-F.C. is Senior Research Associate of FRS-FNRS. R.A. gratefully acknowledges the support from the Spanish Ministerio de Economia y Competitividad (MAT2016-79776-P), from the Government of Aragon and the European Social Fund under the project “Construyendo Europa desde Aragon” 2014–2020 (Grant No. E/26), and from the European Union H2020 program ETN project “Enabling Excellence” Grant Agreement No. 642742. E.L. was supported by the Catalan Institution for Research and Advanced Studies via the ICREA Academia Award and MINECO-FEDER (grant no. TEC2015-71663-R) and J.C.-C. was supported by Universitat Rovira i Virgili via a Martí i Franquès predoctoral fellowship. This work was supported by the Helmholtz-Zentrum Berlin für Materialien und Energie within a bilateral Russian–German Laboratory program. A.A.M. acknowledges support from DFG, Grant No. LA655/13-2. D.V.V. acknowledges Saint Petersburg State University (SPbU) for research Grant No. 15.61.202.2015.

Display Omitted A method to reduce the contact resistance between metal and semiconductor is proposed.The method consists of the repetition of oxide growth/etching to cure damaged surface.The repetition of oxide growth followed by etching is used to cure damaged surface.The technic was applied to Molybdenum/InGaAs interface on TLM test structure.We report a contact resistivity of 0.71?µm2. The CMOS device channel material for sub-10nm dimensions has been identified to be major challenge as per the International Technology Roadmap for Semiconductors (ITRS). Among the options that are defined by ITRS roadmap is the high mobility III-V based channels. In this paper, we report on new III-V materials showing great potential in achieving nanometric scale transistors in support of applications that require operating at 0.3-0.5V. In the first phase of this research, a special focus was given to Molybdenum/InGaAs contacts in order to set up basic unit processes and characterization techniques. Indeed, the electrical measurement were performed and linked to the interface morphology characterized by Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM) and High Resolution Transmission Electron Microscopy (HRTEM). Kelvin structures of Molybdenum over InGaAs were fabricated as test structures to measure the contact resistance and resistivity of the aforementioned interface. Plasma damages induced during the fins definition by reactive ion etching are known to significantly increase the contact resistivity in III-V based finFET. The digital etch technique is implemented on an unexposed plasma damages sample in order to assess the compatibility of this technique with a finFET process flow. The first set of electrical measurements gives a contact resistance of 0.71?µm2 competitive with existing Mo/InGaAs contact resistance, revealing the compatibility of the digital etch cleaning technique with common MOSFET process flow.

To achieve low contact resistance between metal and III-V material, transmission-line-model (TLM) structures of molybdenum (Mo) were fabricated on indium phosphide (InP) substrate on the top of an indium gallium arsenide (InGaAs) layer grown by molecular beam epitaxy. The contact layer was prepared using a digital etch procedure before metal deposition. The contact resistivity was found to decrease significantly with the cleaning process. High Resolution Transmission & Scanning Electron Microscopy (HRTEM & HRSTEM) investigations revealed that the surface roughness of treated samples was increased. Further analysis of the metal-semiconductor interface using Energy Electron Loss Spectroscopy (EELS) showed that the amount of oxides (InxOy, GaxOy or AsxOy) was significantly decreased for the etched samples. These results suggest that the low contact resistance obtained after digital etching is attributed to the combined effects of the induced surface roughness and oxides removal during the digital etch process.

High permittivity dielectric and metal gate are now the most demanded in advanced CMOS technology to overcome conventional polysilicon gate structure drawbacks. However, existing metal gate fabrication approaches are not capable to meet all the demands in terms of material engineering or fabrication process. In this study, we present a two-step dry and wet etching strategy for the integration of tantalum and titanium nitride full-metal single gate, which offers a perfect vertical, roughness-free sidewall and an ultra high metal/dielectric etch rate selectivity.

Schottky Barrier Height (SBH) lowering at the source/drain contacts appears as an inescapable requirement for CMOS downscaling in the sub-20nm regime that legitimates metallic source/drain technology as a relevant solution. For that sake, we have developed a test structure which enables the extraction of the effective SBH by the combination of experimental data to a transport model taking into account thermionic and tunnel emission. In this study, we demonstrate the compatibility and the cumulative effects of two SBH lowering techniques: dopant segregation integration and wafer-based biaxial tensile strain.

An extensive simulation analysis of silicon-nanoribbon field-effect transistors for the detection of chemical warfare agents has been performed through investigation of the physical behavior of the device. An accurate modeling of the nanoribbon interfaces has been carried out before and after gas exposure by combining simulation, characterization techniques and validation against experiments. A quantitative description of the physical mechanisms involved in the gas detection has been obtained.

International audience; —The top-down fabrication of doped p-type silicon-nanowired (NW) arrays and their application as gas detectors is presented. After surface functionalization with 3-(4-ethynyl-benzyl)-1, 5, 7-trimethyl-3-azabicyclo [3.3.1] nonane-7-methanol molecules, the wires were subjected to an organophosphorous simulant, and both static and dynamic measurements were performed. A current gain of 4 × 10 6 is obtained upon the detection of the subpart-per-million concentration of a nerve-agent simu-lant. This represents a four-decade improvement over previous demonstration based on nanoribbons, proving better sensing capabilities of NWs. Technology-computer-aided-design simulations before and after gas detection have been performed to gain insight into the physical mechanisms involved in the gas detection and to investigate the impact of the surface-to-volume ratio on sensor sensitivity.

Top-down fabrication and electrical characterization of undoped p-type silicon nanowires with and without stress using a 4-point bending fixture are shown. Uniaxial tensile stress values of around 200 MPa are possible with the bending fixture. Giant piezoresistance is measured for wires of 50 nm-thick and widths from 25 nm to 1 µm. Nonlinear characteristics at high stress level and impact of backgate bias on piezoresistance coefficient are presented for the first time.