Zero-bias offsets in I–V characteristics of the staircase type quantum well infrared photodetectors

In this work, observed zero-bias offsets in I–V characteristics and differences in J–V characteristics of staircase quantum well infrared photodetectors were investigated. Temperature and voltage sweep rate dependence of the zero-bias offsets were studied on mesa structures shaped in different diameters. Furthermore, effect of mesa diameter on J–V characteristics was investigated. The temperature, initial bias voltage and voltage sweep rate dependence of the zero-bias offsets were explained by a qualitative model, which is based on a RC equivalent circuit of the quantum well infrared photodetector.