Surface Barrier Diodes on Semiconducting KTaO3

A combination of capacitance, I-V, and photoresponse data is presented for metal-semiconductor junctions on KTaO3. Results are in good agreement with the Schottky theory for doping levels below 1018 cm−3. Substantial deviations occur for higher doped samples. Measured barrier potentials do not correlate with either the metal work function or the metal electronegativity, and appear to be strongly affected by strains at the metal-semiconductor interface. In the case of Cu and Au, structure in the photoresponse data associated with an energy-dependent density-of-states is observed.