Mg/硫化GaSb(100)界面的同步辐射光电子能谱研究

SRPES Studies of Chemicl Bonds and Interface on Sulfurizide GaSb(100)by Mg Deposition

利用同步辐射光电子谱,研究了[NH_4]_2S_x处理GaSb(100)表面的成键特性和化学组成及室温下Mg淀积到钝化GaSb表面的界面反应和电子结构.结果发现,经过[NH_4]_2S_x处理的GaSb表面,Ca和Sb的氧化物消失,生成Ga和Sb薄层硫化物钝化层.钝化样品退火处理后,Sb_xS_y 硫化物不稳定,分解或进一步与衬底GaSb反应生成单质Sb和GaS成分.室温下,金属Mg淀积到该钝化表面,它与表面GaS成分发生置换反应,生成金属Ca偏析到外表面,而硫以化合态形式保留在界面,Mg淀积在[NH_4]_2S_x处理n-GaSb(100)表面肖特基势垒的形成,由SRPES方法首次测得为0.3eV.

Synchrotron radiation photoelectron spectroscopy (SRPES)has been used to ivestigate the chemical bonds and electronic states of the [NH4]2Sx treated GaSb(100) surface. We find that the sulfides of Ga and Sb are formed on GaSb surface by [NH4]2Sx treatment, and the oxides of Ga and Sb are removed out. After the passivated surface being annealed, a stable sulfur passivation layer formed on the surface is terminated with Ga-S bonds, while the SbxSy compounds are decomposed or further react with substrate into elemantal Sb and Ga-S components. These results imply that ammonia sulfide has a passivating role for GaSb, it may improve the electronic, optical properties of the GaSb base devices. At room temperature, Mg deposition in the passivated surface was also investigated. It was found that Ga can be exchanged by Mg atoms and diffuse into Mg overlayer. Moreover, Schottky barrier height of the Mg/S/GaSb system was determined about 0. 3eV by SRPES mesurements.