Investigation of tribological and mechanical properties of Nb-Al-N coatings before and after annealing
Coatings Nb-Al-N were deposited on a silicon substrate under argon and nitrogen by magnetron sputtering at a substrate temperature of 350 °C and a constant current of 250 mA at the aluminum cathode. The analysis of the dependence chemical composition, morphology, structure and mechanical properties of the annealing temperature were performed for different series of coatings. Coatings demonstrated high thermal stability after annealing to 1000 °C.
Effects of Heat-treatment on Mechanical Properties and Corrosion Resistance of NbN Films☆
Abstract The NbN and Nb films are prepared by the technique of radio frequency (RF) magnetron sputtering and heat-treated at 300 °C and 400 °C respectively in the present work. The influences of heat-treatment on the morphology, chemical composition, structure, nanomechanical properties and corrosion resistance of the films are studied. Results show that the particles in the films prepared by the above method are all in nano-size. The polygon shaped particles in the Nb films are very thin and small, while the particles in the NbN films prepared under the same condition are pebble-like, larger, and more compact. The nanomechanical properties and corrosion resistance of both the films are improved apparently after the heat-treatment. The corrosion resistance and mechanical properties of NbN film are always better than those of Nb film. The mechanism about the heat-treatment on the property considering the structural evolution is also discussed in this paper.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.