p+-InAsSbP/n-InAs photodiodes for IR optoelectronic sensors

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.