Heterojunctions have been fabricated of p-type amorphous gallium
arsenide (a-GaAs) thin films onto n-type silicon (n-Si) single crystals using
thermal evaporation method. Current density-voltage and capacitance–voltage
measurements have been performed to determine the electrical properties of
the structures. Rectifying current involves tunneling and is explained by a
multi-tunneling capture-emission model. The reverse current is limited by the
carrier generation process. The capacitance-voltage behavior indicates an
abrupt interface with a main-band discontinuity of 0.25 eV occurs in the
valance band.