Injection photodiode based on a p-Si-n-CdS-n +-CdS structure

Abstract

An injection photodiode with a high room-temperature rectification factor (105) is developed based on a p-Si-n-CdS-n +-CdS structure. It is shown that the light and dark current-voltage characteristics of the structure have identical features. It is found that the mode of “long” diodes is implemented in the structure at current densities of I = 10−2−5 × 10−4 A/cm2; in this case, the integral (S int) and spectral (S λ) sensitivities sharply increase. It is shown that S int = 2.8 × 104 A/lm (3 × 106 A/W) for an illuminance of E = 0.1 lux and S λ = 2.3 × 104 A/W under laser irradiation with λ = 625 nm and a power of P = 10 μW/cm2 at a bias voltage of V = 20 V. It is shown that the mechanism of photocurrent amplification is predominantly associated with ambipolar carrier-mobility modulation.