Analysis of the dark current in the bulk of InAs diode detectors

We report on analysis and comparison of the dark current characteristics between InAs p-n and p-i-n diodes at the temperature range from 30 to 300 K. The situation that the dark current is completely due to the bulk instead of the surface leakage is made sure by passivation treatment. The experimental results agree well with a tunnel diode model in which the p-n and p-i-n diodes are described, respectively, with a linear electrical field and a constant electrical field. The diffusion current in our diodes is dominated by the electron diffusion in the p-type material. Through this model and detailed analysis, we conclude that the tunneling current can be suppressed with an intrinsic layer and a low n-type doping density while the diffusion current can be decreased with a high p-type doping density. The advantage of the p-i-n structure is not only to cut down the tunneling current but also to increase the uniformity. In terms of this model, a new p-i-n diode is designed to dramatically increase its zero-bias resistance area product and improve the detector performance. (C) 1996 American Institute of Physics.