高周波マグネトロンスパッタリング法により作製した結晶性ＧａＴｅ薄膜の膜構造と光吸収スペクトル

Abstract

Crystallized thin films of layered semiconductor GaTe were fabricated on silica glass by RF magnetron sputtering in H2 and Ar atmospheres. The structure and optical characteristics of these GaTe films were investigated by X-ray diffraction, atomic force microscope measurements and UV-Vis spectrophotometer measurements. The XRD patterns of the films deposited at substrate temperature up to 600°C in argon gas only showed an amorphours structure. The films fabricated with an H2 and Ar gas mixture were crystallized at a hydrogen mole fraction of more than 1 mol.%. Crystallinity and the orientation of the crystalline films showed a dependence on the hydrogen mole fraction. The photo absorption edges showed a direct transition with an optical gap of 1.57 eV, which was in good agreement with that of single GaTe crystals (1.66 eV). The processes of film deposition and crystallization were strongly affected by the presence of hydrogen.