CHARACTER OF SURFACE-STATES AT GAAS-SURFACES

The analysis of field effect measurements and of thermally stimulated currents allows to derive the general shape of the distribution of surface states for GaAs surfaces. The density of fast surface states consists out of a continuous distribution with a minimum near the middle of the energy gap as well as increasing tails towards the band edges. About the middle of the forbidden gap a peaking distribution is superposed to the continuous distribution. The response to physical and chemical influence allows to discriminate between intrinsic and extrinsic surface states. This distribution of surface states qualitatively yields a satisfactory description of the experimental results. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA