화학공학소재연구정보센터
Thin Solid Films, Vol.360, No.1-2, 278-282, 2000
Epitaxial bilayered Nb-Mo(001) films: growth, characterization and size effect in electron conductivity
Mo-Nb and Nb-Mo epitaxial thin (10-200 nm) films growth on the r- sapphire plane under ultra high vacuum by laser ablation deposition at the growth temperature 750 degrees C were tested. Grown films were characterized by reflected high energy electron diffraction (RHEED), X-ray diffraction (XRD), scanning atomic force microscopy and electron transport measurements. It was found that bilayered films are high quality heteroepitaxial single-crystalline (001) films with low surface roughness (0.3-0.5 nm) and large residual electron mean free path, compared to the film thickness. The superconducting transition temperature of Nb-Mo films with equal layer thickness varies from 5 up to 9 K as the thickness increases from 10 to 100 nm. Physical properties of the films are close to each other both for Nb/Mo and Mo/Nb films of equal layer thickness and do not depend on the alternation of Mo and Nb layers. This suggests the same film structure quality and mutual epitaxy of the metals. The size dependence of electron conductivity of bilayered Mo-Nb films showed that it is determined by the dimension of individual layers, constituting the film, where the effect of 'contact' potential formed at the interface between Mo and Nb layers and a fluctuation of him bending is important.