INVESTIGATION OF THE SURFACE PROPERTIES OF EPITAXIAL n-TYPE GaAs FILMS AT LOW TEMPERATURES.

The results are given of investigations of surface-sensitive effects observed at 20 degree K in epitaxial films of n-type GaAs (the temperature dependence of the mobility in these films indicated a high purity). A considerable low-temperature carrier depletion was observed on the original surfaces of the epitaxial films. This was observed on the free side and the substrate sides, but on the free side the depletion did not exceed half the width of the forbidden band (Y//s//o similar 0. 4-0. 8 eV). It was demonstrated that the doping profiles of the films could be determined by the field effect method without destruction of the film. The density (N//s//s similar 10**1**2 cm** minus **2. eV** minus **1) and the energy position ( DELTA E//t similar 0. 2 eV) of the acceptor levels near the bottom of the conduction band were determined.