Chemisorption of iodine on In- and Sb-terminated InSb(001)

The chemisorption of I-2 on the In-terminated InSb(001)-c(8 x 2) and Sb-ter minated InSb(001)-c(4 x 4) surfaces was investigated with synchrotron-based soft X-ray photoelectron spectroscopy and low-energy electron diffraction. For both terminations, the predominant species formed is InI2, and the sur faces become disordered. Further analysis suggests that iodine adsorption i nduces In to migrate from the bulk up to the surface. These results are com pared to results for similar systems. It is suggested that the ability of I nI2 to form on the surface is critical in determining the reaction pathway. InI2 is readily formed because of the relatively large lattice spacing and the relatively weak In-Sb bond strength, as compared to other III-V materi als. Thus, the reaction of I-2 with InSb can proceed more completely, and t he surface product distribution more closely reflects the bulk chemical the rmodynamics. (C) 2000 Elsevier Science B.V. All rights reserved.