氢致LaMg2Ni合金薄膜的光电性能变化

采用电子束蒸发法沉积LaNi/Mg多层膜，再于350℃真空退火合金化的方法制备了厚度为375nm的LaMg₂Ni合金薄膜.在吸、放氢过程中，该合金薄膜能够在高反射的金属态和透明的半导体态之间可逆地转变.在可见光波长范围内的平均透射率和电阻率在反射态和透明态之间的对比度大于10⁴.利用扫描电子显微镜和原子力显微镜观察了吸放氢前后薄膜的表面及剖面形貌.结果表明，在氢化过程中薄膜表面的平整性降低且不可恢复，是脱氢态中出现低反射现象的主要原因. 关键词： 薄膜 光电性能 氢 形貌

Hydrogen-induced changes in optical and electrical properties of LaMg2Ni alloy film

A 375nm thick LaMg₂Ni alloy thin film was prepared by electron beam evaporation using LaNi, Mg and Ni targets, and followed by vacuum annealing at 350℃. Upon hydrogen loading/unloading, the reversible conversion from a metallic, reflecting state to a semiconducting, color-neutral transparent state was observed in the as-prepared film. The contrast ratios in both the transmission (400—900nm) and the resistivity between the reflecting state and the transparent state are over four orders of magnitude. The surface and the cross-section of the alloy films before and after hydrogenation were observed by scanning electron microscope and atomic force microscope, which showed that the lower reflection observed in the dehydrogenated film is due to the rough surface originating from the first hydrogenation.