GaAs Wafers Possessing Facet-Dependent Electrical Conductivity Properties

Intrinsic GaAs(100) and (111) wafers were cut to expose {110} side faces for facet-specific electrical conductivity measurements. Using tungsten probes to make electrical contacts with the wafers, the {111} surface displays much larger current than the {100} and least conductive {110} surfaces, showing that facet-dependent electrical properties are also observable in GaAs crystals. Different degrees of surface band bending are used to explain the electrical facet effects. While symmetricI-Vresponses were collected for the {100}/{110} facet combination, asymmetricI-Vcurves were recorded for the {110}/{111} facet combination. Adjusted band diagrams with tunable surface band bending are presented to explain the current-rectifying behaviors. The current rectification effect can be applied to fabricate novel transistors.