The Energy Distribution of Field‐Emitted Electrons from GaAs

Measurements of the energy distribution of field‐emitted electrons from clean GaAs surfaces indicate that the emission originates from the valence band. The distributions are found to be considerably wider than is predicted by theory despite the high resolution of the apparatus. The Fermi level at the surface of low‐resistivity n‐type material is found to be stabilized 0.54 eV below the conduction band edge indicating a high density of surface states. The surface state density is estimated to be greater than 2.8 × 10 13 cm −2 . Emission from within the forbidden gap is also reported.