Uncooled InAs photodiodes for optoelectronic sensors

InAs photodiodes were prepared by short-term cadmium diffusion into substrates with n-type conductivity. This preparation technique results in formation of p+-p-n-n+ diodes with compensated region embedded between two doped regions. Experimental data are explained by suppression of Auger recombination in active compensated region. Electrical and photoelectrical properties of photodiodes were investigated in the temperature range 77-295 K. It is shown that the total dark current is determined by the diffusion carrier transport mechanism. The diffused photodiodes exhibit higher photosensitivity in the short wavelength region due to presence of built-in electric field at the surface. Their threshold parameters are found to be approximately the same as in commercially available photodiodes.