Carrier transport mechanisms in InSb diffusion p-n junctions

Abstract

The linearly-graded p-n junctions were prepared by diffusion of cadmium into n-InSb(100) substrate with the electron concentration n ~ 1.6*10¹⁵ cm⁻³ at the temperature T = 77 K. Passivation and protection of mesa structures have been carried out using thin films of CdTe. Forward and reverse current-voltage characteristics were investigated within the temperature range 77…156 K. It has been found that the total dark current consists of generation-recombination and tunneling current components, which are dominant at high (T = 120…156 K) and low (T < 120 K) temperatures, respectively. Experimental results have been explained using the model of a nonhomogeneous p-n junction. It has been shown that in the linearly-graded p-n junction with the rather thick (~1 m) depletion region tunneling current flows through the states related to dislocations in the depletion region. The performed estimation of electrical parameters of diffusion InSb p-n junctions allows to predict behavior of InSb-based photodiodes at operation temperatures T > 77 K.