Substrate chemical etching prior to molecularhyphen;beam epitaxy: An xhyphen;ray photoelectron spectroscopy study of GaAs lcub;001rcub; surfaces etched by the H2SO4hyphen;H2O2hyphen;H2O solution

摘要

Xhyphen;ray photoelectron spectroscopy has been performed in order to investigate the effects of the chemical etching of GaAs lcub;001rcub; surfaces by the H2SO4/H2O2/H2O solution used following the procedure currently practiced in the molecularhyphen;beamhyphen;epitaxy technique. It is demonstrated that, in contrast to what is generally believed, rinsing in running deionized water after etching does not produce any passivating oxide film on the surface. The surfacehyphen;oxidized phases are only due to the sample manipulation in air after etching. This oxidation process is enhanced by the sample heating for indium soldering on the sample holder. It is shown that the surfacehyphen;oxidized phases can be avoided by handling the sample under an inert atmosphere. Results of thermal desorption of the surfacehyphen;oxidized phases are also given.