[en] Shape memory alloy TiNi films were prepared on Si and Si/SiO₂ by co-sputtering of TiNi target (Ti 50 at.% and Ni 50 at.%) and Ti target (99.999 at.%). When comparing Si/TiNi with Si/SiO₂/TiNi, the addition of SiO₂ sandwich layer did not result in significant change in the crystalline structures and shape memory properties. The SiO₂ sandwich layer served as an effective diffusion barrier in preventing formation of interfacial titanium silicide at the expense of film adhesion. As revealed by X-ray photoelectron spectroscopy, under the same conditions, the interfacial diffusion zone in Si/TiNi system was approximately 120 nm while in Si/SiO₂/TiNi system the diffusion zone was only approximately 30 nm--a four-fold reduction in inter diffusion. Meanwhile, the scratch adhesion testing registered a sharp drop in adhesion of the film from 170 mN in Si/TiNi system to 60 mN in Si/SiO₂/TiNi system

[en] InSbN alloys are fabricated by two-step nitrogen ion implantation into InSb (111) wafers. X-ray photoelectron spectroscopy indicates that most of the implanted nitrogen ions substitute Sb to form In-N bonds. The percentage of the In-N bonds is found to decrease with the increase in the implanted nitrogen. Such alloys can effectively detect long wavelength infrared radiation and the absorption peak energies can be controlled by monitoring the implanted nitrogen dose. The measured peak wavelengths are consistent with the band gaps of the alloys calculated using a ten-band k·p model

[en] Nanocrystalline titanium carbide (TiC) thin films were prepared by magnetron sputtering deposition at 473 K. The effect of substrate bias on microstructure and mechanical properties was studied in details using X-ray photoelectron spectroscopy, X-ray diffraction, field emission scanning electron microscopy, indentation and scanning microscratch. The TiC films exhibit a (111) preferential orientation. Substrate bias decreases grain size and deposition rate of the TiC films. The TiC films have columnar structure which becomes finer at high substrate bias. Nanoindentation hardness, Young's modulus, and toughness of the films are increased as the substrate bias goes up. However, the adhesion peaks at substrate bias of - 100 V and drops when bias is increased further

[en] Highlights: • TiNx films were prepared by ion source assisted magnetron sputtering. • Re-sputtering effect enhanced with increasing substrate bias voltage. • Both hardness and toughness of TiNx films were studied. • Tafel curve and EIS were measured to identify the corrosion resistance. • A corrosion model was provided for the explanation of corrosion mechanism. -- Abstract: Titanium nitride (TiNx) films were deposited on 304 stainless steel and silicon (100) wafers by ion source assisted magnetron sputtering. The effect of substrate bias voltage on the preparation and properties of TiNx films was investigated. The results show that as the substrate bias voltage increases from 0 V to −400 V, the deposition rate of TiNx film decreases significantly and the density increases, which can be attributed to the re-sputtering effect at high ion bombardment. The texture of TiNx films varies gradually from (111) to (200) with the increase of energy delivered into the growing film. The hardness of the film deposited under −200 V bias voltage reaches the maximum value, 12.9 GPa. Meanwhile, the toughness and corrosion resistance of the film reach a maximum at a bias voltage of −400 V. In conclusion, the density, hardness, toughness and corrosion resistance of TiNx films can be increased by changing the substrate bias voltage.

[en] Highlights: • CVD BN coating could effectively improve the mechanical properties of silica optical fibers by curing the defects and generating residual compressive stress in the fiber. • The critical thickness of BN coating in this system at which the strength changes from fiber-controlled into fiber-matrix-controlled is 0.5 μm and the critical thickness at which the strength changes from fiber-matrix-controlled into matrix-controlled is 1 μm. • BN coated silica optical fiber keeps a linear deformation behavior during both tensile test and creep test, which is beneficial to its application as a strain sensor. • CVD BN can not only be a protective coating but also be a total reflection coating of silica optical fiber from light leakage at both room temperature and 700 °C. -- Abstract: Boron nitride light-leakage-proof coating was prepared via chemical vapor deposition (CVD) process on silica optical fiber for sensing applications at high temperatures. Compared with the original fiber, the tensile strength of BN coated fiber was more than two times higher at both room temperature and 700 °C. It was found that the critical value of BN coating thickness at which the strength changes from fiber-controlled into fiber-matrix-controlled is 0.5 μm and that at which the strength changes from fiber-matrix-controlled into matrix-controlled is 1 μm. Moreover, BN coated silica optical fiber exhibited favorable creep resistance at 700 °C. Furthermore, BN coated silica optical fiber performed better compared with the uncoated fiber in terms of optical property. Hence, CVD BN is suitable as a light-leakage-proof coating of silica optical fiber.

[en] Reliability of the Cu/low-k structure is a serious concern since the metal/dielectric interface is generally weak. The adhesion of the Ta/polyarylene ether interfaces with and without electron beam (EB) treatment was investigated by four-point bending test, x-ray photoelectron spectroscopy, and density functional theory. Higher adhesion energy (G_c) was achieved with low-dose EB treatment, attributed to the strong Ta-arene interaction. However, high-dose EB breaks the aromatic rings partially, resulting in fewer available sites for Ta-arene bonding, leading to lower adhesion. It is suggested that the amount of carbon atoms involved in bonding with the metal is the key to improve the Ta/polymer adhesion

[en] To combat the high residual stress problem in monolayer diamond-like carbon coatings, this paper fabricated multilayer diamond-like carbon coatings with alternate soft and hard layers via alternating bias during magnetron sputtering. The surface, cross sectional morphology, bonding structures and mechanical properties are investigated. The atomic force microscopy images indicate low bias results in rougher surface with large graphite clusters and voids suggesting low coating density. The multilayered coatings demonstrate relatively smooth surface stemming from higher bias. The cross sectional images from field emission scanning electron microscopy indicate coating thickness decreases as substrate bias increases and confirm that higher bias results in denser coating. Delamination is observed in monolayer coatings due to high residual stress. The trend of sp³/sp² fraction estimated by X-ray photoelectron spectroscopy is consistent with that of I_D/I_G ratios from Raman spectra, indicating the change of bonding structure with change of substrate bias. Hardness of multilayer diamond-like carbon coating is comparable to the coatings deposited at low constant bias but the adhesion strength and toughness are significantly improved. Alternately biased sputtering deposition provides an alternative when combination of hardness, toughness and adhesion strength is needed in an all diamond-like carbon coating.

[en] A quick and simple method was developed for the study of the interaction between Fe-Cr metallic interconnect and Sr-doped LaMnO₃ (LSM) materials using the LSM powders without the high temperature sintering step of the electrode coating. The deposition of Cr species on the LSM powder/Y₂O₃-ZrO₂ (YSZ) electrolyte interface has been found to be significantly dependent on the flow field of the metallic interconnect. The Cr deposition was far more significant at the LSM/YSZ interface areas under the rib of the interconnect as compared to that under the channel of the interconnect. The electrochemical behavior for the O₂ reduction and Cr deposition on the LSM powders are very similar to that observed for the reaction on the LSM electrode coatings pre-sintered at 1150 deg. C. The result demonstrates the feasibility of the direct investigation of the Cr deposition process on the oxide powders

[en] In this work, a wire-shaped perovskite solar cell based on TiO_2 nanotube (TNT) arrays is demonstrated for the first time by integrating a perovskite absorber on TNT-coated Ti wire. Anodization was adopted for the conformal growth of TNTs on Ti wire, together with the simultaneous formation of a compact TiO_2 layer. A sequential step dipping process is employed to produce a uniform and compact perovskite layer on top of TNTs with conformal coverage as the efficient light absorber. Transparent carbon nanotube film is wrapped around Ti wire as the hole collector and counter electrode. The integrated perovskite solar cell wire by facile fabrication approaches shows a promising future in portable and wearable textile electronics. (letter)

[en] Amorphous hydrogenated carbon films were prepared by hot filament Plasma Enhanced Chemical Vapor Deposition using acetylene as precursor. NiP-coated Al substrate was sputtered with thin layer of ruthenium film prior to carbon deposition for its impact on carbon film growth. Film thickness measured and fitted using X-ray Reflectometry showed carbon film growth is an exothermic reaction with apparent activation energy of 914.6 J mol^-1 in the temperature range studied. Carbon film density and surface roughness changed with substrate temperature, more profound when substrate is pre-heated at 300 ^oC and above, in sync with abrupt I_D/I_G increase at temperature higher than 300 ^oC. Substrate temperature higher than 200 ^oC and below 300 ^oC is preferred for hard and dense structure. Higher deposition rate and porosity were observed at higher C₂H₂ flow rate due to more H incorporation. Film surface morphology studied by Atomic Force Microscope showed Root Mean Square roughness increased at higher C₂H₂ flow rate due to less energetic ion peening effect. Atomic bonding structure with sp² and sp³ contents in the films deposited at varied temperature and C₂H₂ flow was analyzed using XPS.