Dark current and 1/f noise in forward biased InAs photodiodes

Abstract

(en) Dark current and low-frequency noise are studied in forward biased InAs photodiodes in the temperature range 77–290 K. Photodiodes were fabricated by diffusion of Cd into n-InAs single crystal substrates. It is shown that at temperatures >130 K the forward current is determined by the recombination of charge carriers with the participation of deep states in the middle of the band gap. At these temperatures, a correlation is found between forward current and 1/f noise. At lower temperatures, the forward current and noise is analyzed within a model of inhomogeneous p-n junction caused by dislocations in the depletion region. Experimental evidence has been obtained that multiple carrier tunneling is the main transport mechanism at low temperatures, which leads to an increase in low-frequency noise.