Injection Photodiode Based on a p-Si-n-CdS-n+-CdS Structure

An injection photodiode with a high room-temperature rectification factor (10(5)) 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 x 10(-4) A/cm(2); in this case, the integral (S-int) and spectral (S-lambda) sensitivities sharply increase. It is shown that S-int = 2.8 x 104 A/lm (3 x 10(6) A/W) for an illuminance of E = 0.1 lux and S 2.3 x 10(4) A/W under laser irradiation with lambda = 625 nm and a power of P= 10 mu W/cm(2) 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.