Shanghai Institute of Technical Physics,Chinese Academy of Science
the National key Research and Development Program of China
The junction is prepared at the high composition end of nonlinear composition region and linear composition region respectively, and the photoelectric performance of HgCdTe detector with component gradient is studied. It is found that the change of the normalized response spectrum and the responsivity with temperature is different between two samples. To calculate the built-in electric field of composition gradient in two sample at different temperatures, the results show that the built-in electric field generated by the linear composition distribution is 100V/cm ~ 200V/cm, while the built-in electric field generated by the nonlinear composition distribution makes the electric field on surface of the sample as high as 2000V/cm. The analysis indicates that the influence of the built-in electric field generated by composition gradient in the junction of the two samples on the movement of the minority carrier is the main reason for the difference of the photoelectric performance with temperature, and the built-in electric field generated by the nonlinear composition distribution changing with temperature makes the responsivity of the sample show three different trends. Through the analysis of response spectrum and responsivity with different temperatures, it is shown that using the built-in electric field generated by the nonlinear composition distribution which is controlled by temperature can reduce the concentration of photogenerated carriers in the junction region and increase the hole drift speed in the junction region, which is conducive to reducing space charge effect and provides a new design idea for improving the saturation threshold of HgCdTe detector under large injection.