The structural, chemical, and electronic properties of a stable GaS/GaAs interface

A stable GaS passivating layer was deposited on GaAs using alpha-Ga2S3 powd er as a single-source precursor. Both good crystal quality and clean GaS/Ga As interface were achieved. Electron-energy-loss spectra showed that the su lfide material has a band gap of 3.0 eV. The valence band discontinuity of the heterostructure was determined to be 1.9 eV from a series of ultraviole t photoelectron spectra with increasing deposition thickness. Al/GaS/GaAs m etal-insulator-semiconductor structures exhibited typical high frequency ca pacitor versus voltage (C-V) behavior with very small loop hysteresis. The C-V curves showed no aging after 20 months. (C) 1999 American Institute of Physics. [S0021-8979(99)00424-7].