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InAs photodiodes were prepared by short-te rm 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 approximatel y the same as in commercially available photodiodes. Keywords: InAs, infrared photodiodes, threshold parameters, transport mechanisms 1.INTRODUCTION Mid-wavelength infrared (MWIR) photodetectors, light-emitting diodes (LED) and lasers are regarded as important components of the next generation optoelectronic sensors for monitoring of atmospheric pollutants, since most of industrial gases, including methane, have distinct absorption bands in this spectral region [1-3]. Also, there is need in development sensors for coal mines, where detecti on condition has essential difficulties such as high contents of coal dust; sudden burst of methane and accompanying gases (ammonia, carbon oxide and dioxide, hydrogen sulphide, sulphur and nitrogen oxides, etc.) during coal mining; increased temperature L =30-35 |
