Doping concentration is the key factor affecting the performance of infrared detectors.
Based on photovoltaic HgCdTe infrared photodetectors, in order to compute the response speed in
engineering applications precisely and fastly, a theoretical estimation model is proposed. At first,
according to continuity equation of PN junctions that are radiated by infrared radiation, the mechanism
of PN junctions in a typical working situation is analyzed and an approximate solving method is
established, which shows the analytic expression of the relationship between the response speed of
photovoltaic infrared photodetectors and the doping concentration s. Then the response speed of
photovoltaic HgCdTe infrared photodetectors is compared to that of photoconductive photodetectors.
In the end, the error of the estimation model is checked, which is done through numerical analysis. The
results indicate that the response speed rises with the doping concentration increasing as the error
increases, the estimation model proposed brings the maximum error of 5.9%, if the doping
concentration is 1021 per cubic centimeter.