The investigation of the transient photovoltage in HgCdTe infrated photovoltaic detectors

The changed polarity of transient photovoltage (TPA) from negative to positive induced by ultra fast lasers illumination is studied in the HgCdTe p-n junction photovoltage detector. The negative photovoltaic-response decrease obviously and even disappear by blocking the laser beam with an aperture to limit the illumination area of the linear array detectors. A combined theoretical model of p-n junction and Schottky contact can explain this new phenomenon well. Using the TPA technique and the combined model, the characters of p-n junction and Schottky contact will be distinguished. Therefore, it could be used in characterizing the Ohmic contact of the detectors electrodes, and its sensitivity is expected to be much higher than the steady states methods.