Coverage analysis of a sulfur-terminated GaAs(001)-(2x6) surface: the effect of double sulfur-treatment

Sulfur-terminated GaAs(001)-(2 x 6) surfaces have been investigated by photoelectron and Auger electron spectroscopy. Surface coverages of S and As are estimated from the angle dependence of electron emission to evaluate the effect of double S-treatment, which is a preparation technique developed by Tsukamoto et al. It is found that a large amount of As remains on the surface after the first S-treatment and that a large portion of the residual As is replaced with S in the second S-treatment. This fact explains the results of the scanning tunneling microscopy observation that the surface homogeneity is significantly improved by the double S-treatment. (C) 1998 Elsevier Science B.V. All rights reserved.