STRUCTURE OF S ON PASSIVATED GAAS (100)

X-ray photoelectron spectroscopy (XPS) and E-polarization-dependent S K-edge x-ray absorption near-edge structure (XANES) are used to charac terize the chemical structure and site location of S on the (NH4)2S-tr eated GaAs (100) surface. XPS studies show that S forms chemical bonds with both Ga and As on surfaces treated only with (NH4)2S. After rece iving a sufficient water rinse, only Ga-S bonds remain on the surface. Photon E polarization-dependent XANES studies show that S is bridge b onded to Ga in the [011] azimuth.