Auger electron spectroscopy and low-energy electron diffraction investigation of the InSb(110)+Ag system at 10–300 K with θ=0–20 monolayers

Abstract

The Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) methods have been employed to study the film growth processes of the high-vacuum-cleaved InSb(110) surface at 10 and 300 K in the coverage interval from 0 to 20 monolayers (ML). The sample evolution in the process of heating up to room temperature after the Ag deposition at 8 K, and in the process of cooling down to 10 K after the deposition at 300 K has been investigated. A comparison of the Auger signals obtained in the process of deposition at 10 and 300 K, and in the process of heating of low-temperature-deposited samples has shown that at 10 K the depth distribution of the Ag atoms has a statistic character, and at room temperature the film growth is accompanied by the island formation. The conclusion on the In-atom diffusion through the silver film is suggested by the interpretation of the Auger spectra, especially of those taken in the process of heating the samples. It is found that the deposition at 300 K leads only to an increase of homogeneous (θ≲10–12) or inhomogeneous (θ≳10–12) backgrounds, the InSb(110)-1×1 spots being conserved. A reversible ordering in the film is observed at cooling. The 10-K deposition, with θ≊1, leads to the appearance of a strong background and to the disappearance of all the diffraction spots. With θ≳4.5 the structure appears that is conserved at heating up to 300 K and corresponds to a (100) plane of the Ag body centered cubic (bcc) structure. In this case (110)Agbcc//(110)InSb, and the analogous crystallographic directions in a (110) plane of either structure are coincident. The process of heating up to room temperature of the samples with θ=1–4.5, obtained at 10 K, gives rise to both the substrate diffraction spots and complementary ones, caused by the adsorbed silver.