The adsorption and desorption of Te on GaAs (100) has been investigated using Soft X-ray Spectroscopy (SXS) and X-ray Photoelectron Spectroscopy (XPS). The SXS measurements have been done at the Brazilian synchrotron facility LNLS, and the XPS study was performed using laboratory sources. The samples were MBE GaAs (100) layers covered in-situ by Te from an effusion cell. Two families of samples were studied: samples analyzed in-situ, and samples that were exposed to air for at least one week. The desorption of Te of the non-oxidized samples indicates that traces of Te remains in the surfaces for temperatures as high as 680 °C. However, for the case of the oxidized samples, the Te film sublimates easily at around of 250 °C, leaving a clean GaAs surface. It seems that the oxidized Te film works as a suitable protection for epitaxial GaAs layers.
