Polarity Effects in InSb Alloyed p-n Junctions

The shape dependence of the profiles of alloy junctions formed on {111} and {1̄1̄1̄} surfaces of InSb has been studied as a function of alloying conditions. Polarity-dependent effects are found which may be attributed to different dissolution rates for {111} and {1̄1̄1̄} surfaces. Direct evidence of this difference is presented. By proper choice of alloying conditions it is possible to obtain planar junctions on both types of surface. The rectification ratios of such junctions prepared on either surface range from 107 to 2×108, at 250 mV. The polar differences in the current-voltage characteristics of these junctions are small and tentatively attributed to polarity-dependent surface effects.