Characterization and Substrate-Temperature Dependence of Crystalline State of GaAs Grown by Molecular Beam Epitaxy

Abstract

Thin films of GaAs single crystal were prepared successfully on GaAs (100) substrates by molecular beam epitaxy using an ultrahigh vacuum system with effusion cells and a quadrupole mass analyzer. The dependence of the quality of the GaAs film on the substrate temperature, T_s, was investigated in detail at a constant Ga and As₂ arrival rate. The epitaxial process was studied in situ with a high energy electron diffraction (HEED) system. The analysis and characterization of the prepared GaAs films were made with a scanning electron microscope, an ion microprobe analyzer, an ESCA photoelectron spectrometer and photoluminescence measurements. These measurements indicate that GaAs films grown at 480\lesssimT_s\lesssim530°C by molecular beam epitaxy have smooth surface and nearly the same quality as bulk crystal.