Core-level photoemission study of the Bi-GaAs(111) A interface

Core-level photoemission spectra of the As 3d, Ga 3d and Bi 5d core levels were recorded for the Bi-GaAs (111)A-(2 X 2) surface. From the early stages of Bi growth, there are two distinct chemical environments for Bi. Surface Bi is bonded to both As and Ga atoms. The deposition of approximately 1 ML of Bi removes the dangling bonds from the surface As and Ga atoms, which are associated with the (2 X 2) vacancy-buckling structure. Annealing to 350 degrees C reverses this process and surface dangling bonds for Ga reappear. When the Bi had fully desorbed at 425 degrees C, photoemission and LEED results showed that the surface recovers the (2 X 2) vacancy structure but with a larger degree of surface disorder than that found before the deposition of Bi. (C) 2000 Elsevier Science B.V. All rights reserved.