Evidence for localised electrical conduction through semi-insulating indium phosphide substrates

Abstract

Evidence is provided for the existence of electrical conduction “pipes” through the thickness of iron doped semi-insulating indium phosphide wafers. The pipes have an approximate resistance of 250 kΩ mm −1 and spatial densities as high as 100 cm −2 have been observed. The pipes correlate with a core like feature surrounded by a radially disordered region revealed by electrolytic oxidation at the pipe.