The performance of p+-InAsSbP/n-InAs infrared (IR) photodiodes prepared by liquid phase epitaxy technique
(LPE) is investigated. The current-voltage and capacitance-voltage characteristics, photoresponse and noise spectra are
investigated in the temperature range 77-300 K. The trap-assisted current is calculated and compared with
experimental data. It is found that at near-room temperatures and small reverse biases U ≤ 0.2 V experimental I-U
characteristics are determined by diffusion and generation-recombination mechanisms. The trap-assisted tunnelling is
shown to be dominant at higher reverse biases. The heterojunction photodiodes have superior photoresponse spectra in
comparison with homojunction photodiodes and high threshold parameters.
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.
The addition of comparatively low density of dislocations Ndis less than or equal to 107 cm-2 causes the essential quantitative, and qualitative changes of kinetic coefficients in Hg1-xCdxTe (MCT) crystals. In n-type crystals the electrons concentration increases dramatically, and the electrons mobility decreases. Moreover, the characteristic maxima appears in the electrons Hall coefficient RH and mobility temperature dependency, being an evidence of the existence of the carriers of two types. In p-type crystals we observed the increase of halls concentration and the change of sign of RH with temperature and magnetic field in the low temperature region (T equal to 4.2 divided by 40 K), together with a transition from activation conductivity to metallic one. It was demonstrated, that these changes are caused not by electronic states of the dislocation core directly, but by the point defects, formed in the process of dislocation movement, and concenrated in the gliding planes. The amount of experimental data can be explained within the idea of the formation of the channels of the different type of conductivity connected with dislocations net, in the matrix of the crystal. This net is formed by tubes of the volume space charge around the dislocation core, penetrating throughout the. The dislocation core itself is formed by the line of cations and anions respectively with the dangling bounds of crystalline lattice.
It was shown, that the uniaxial compression leads to the increase of Auger lifetimes in the narrow gap semi-conductors, and to the decrease of the radiative band to band lifetimes. The quantum efficiency can be increased up to 1 on the base of this effect. Experimental results are obtained for InSb an HgCdTe.
The stimulated emission of far IR radiation from uniaxially strained gapless Hg1-xCdxTe was observed experimentally. The mechanism of this effect is proposed with allowance of both the strain-induced transformation of energy spectrum and the transformation of impurity acceptor level in the gapless semiconductor.
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