InSb Diodes under Controlled Surface Conditions

Abstract

The surface of anodized InSb cooled in the dark can be changed from n type over a conductance minimum to p type by controlled illumination. The characteristics of alloyed diodes on n‐ and p‐type base material were studied at 78°K under controlled surface conditions. Under optimal surface conditions the voltage‐current characteristic follows the relation predicted by Sah et al. for space‐charge generation currents. An effective minority carrier lifetime of 2.4×10⁻⁹ for n‐type and 2.8×10⁻⁹ for p‐type InSb is required to fit the data. An anomalous capacitance is observed only if an inversion layer exists at the surface.