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

Synchrotron radiation photoelectron spectroscopy （SRPES）has been used to ivestigate the chemical bonds and electronic states of the NH₄₂S_x treated GaSb（100） surface. We find that the sulfides of Ga and Sb are formed on GaSb surface by NH₄₂S_x 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 Sb_xS_y 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.