Two-Dimensional Arrangement of InSb Epitaxial Nanoscale Crystals on Selenium-Treated Terraced GaAs Substrates

Abstract

Molecular beam epitaxial InSb nanoscale crystals on selenium-treated GaAs substrates have been studied by in situ synchrotron radiation photoelectron spectroscopy (SRPES), in situ reflection high-energy electron diffraction (RHEED), and atomic force microscopy (AFM). The SRPES results show that room-temperature deposited Sb atoms on Se-passivated GaAs were desorbed from the surface when the sample was heated to 200°C, indicating that Sb atoms do not react with the topmost surface Se atoms at this temperature. The results of RHEED pattern observations suggest that InSb nanometer-size islands surrounded by (111) facets are grown on the Se-passivated GaAs surface at 200°C whereas an InSb layer with a nominal thickness of 1 monolayer is formed on the clean GaAs surface. Furthermore, geometrical arrangement of the InSb nanocrystals grown on the Se-treated, terraced GaAs(001) has been characterized by AFM. It has been found that, by using terraced substrates, two-dimensional alignment of InSb nanocrystals can be formed, which implies that this phenomenon is associated with preferential nucleation of InSb on the step edges of the terraces.