ORIGIN OF HIGH RESISTANCE AT THE EPITAXIAL LAYER‐SUBSTRATE INTERFACE OF GaAs GROWN BY VAPOR EPITAXY

A photoluminescence band at 1.40 eV has been observed at 90 °K only at the interface between the epitaxial layer and the substrate in the vapor‐grown GaAs crystal. The defect responsible for the band is considered to correlate with a shift of the Fermi level toward the valence band in this interface region and to be related to the acceptor created in GaAs bulk crystal which is heat treated in H2. The defect may be the deeper of two kinds of acceptors associated with the Si impurity on an As site in GaAs crystal.