Photodetector based on photo memory effect for low light level detection

The response of current-voltage characteristics of the photo memory cell with quantum dot and quantum well are presented. It has good low-light-level sensitivity and very small dark current at low temperature. In order to explore its high sensitive application because of high internal photoconductor gain, the CMOS readout circuits and correlated double sample structure are integrated to acquire small photocurrent and turn to voltage signal. The readout circuits are designed to match 2×8 photodetector arrays. A 632.8 nm He-Ne laser beam shoots on the optics window of photodetector in Dewar at liquid nitrogen temperature. The measured results show that the readout response voltage can reach to 61 mV and 6.1E+07 V/W responsivity under radiation intensity 1 nW with 77.6 ps integration time when biased voltage up to −3 V.