Pulsed trimethylgallium beam scattering from variously reconstructed GaAs surfaces

Abstract

The adsorption of trimethylgallium (TMG) on variously relaxed or reconstructed GaAs surfaces is discussed in terms of precursor-mediated mechanism. Since the TMG molecules trapped in the precursor states are desorbed without permanent sticking from GaAs surfaces with stable structures, the depths of the precursor states for (110), (111) B-( 19 × 19 ) , and (100)-(2 × 4) surfaces are directly determined from the residence time in the precursor state to be (0.38 ± 0.05), (0.32 ± 0.05) and (0.85 ± 0.05) eV, respectively. On a (111)B-(2 × 2) surface, such a deep precursor state is not observed. The obtained surface structure dependence of the precursor state is well explained by the charge distributions in the relaxed or reconstructed surfaces.