Adsorption sites of Te on Si(001)

Using multiple surface science techniques, we have investigated the structure of 0.3-1 Te monolayers adsorbed on Si(0 0 1). X-ray standing waves, low-energy electron diffraction, temperature-programmed desorption, and Auger electron spectroscopy show a relatively poorly-ordered surface. The disorder is due to two nearly degenerate Te adsorption sites, which tends to double the periodicity along one direction of the surface and reduces adatom/substrate mismatch by slightly increasing the separation of adjacent Te atoms. High-temperature anneals around 575 degreesC increase the degree of local and long-range order, while leaving the average local structure unchanged. Our findings are consistent with recent ab initio molecular dynamics simulations but not with experimental studies wherein surfaces were prepared by desorption of CdTe films. (C) 2004 Elsevier B.V. All rights reserved.