Structure and composition of the c(4×4) reconstruction formed during gallium arsenide metalorganic vapor-phase epitaxy

Abstract

Surfaces of GaAs (001) were prepared by metalorganic vapor-phase epitaxy and characterized by scanning tunneling microscopy, x-ray photoelectron spectroscopy, infrared spectroscopy, and low-energy electron diffraction. Upon removal from the reactor, the gallium arsenide surface exhibits a (1×2) reconstruction, which is a disordered variant of the c(4×4). The disorder arises from the presence of adsorbed alkyl groups. Heating the sample to 350 °C desorbs the hydrocarbons and produces a well-ordered c(4×4) structure. A model is proposed for the alkyl-terminated (1×2) reconstruction.