Electrical and Optical Properties of nBn Based on Type-II InAs-GaSb Strained Layer Superlattice Infrared Detectors

An infrared detector based on type-II In As/Ga Sb strain layer superlattice with the n Bn design has been designed. Dark current of the n Bn device was studied through the theoretic calculation and the experiment. The results show that dark current of the theoretic calculation is consistent with the trend of the experimental results. In addition, the p-i-n device was developed, and compared with the n Bn device. Test results present that dark current of the n Bn device is two orders of magnitude lower than dark current of the p-i-n device at 77 K. When the temperature rises to 150 K, dark current of the n Bn device increases by two orders of magnitude, and dark current of the p-i-n device increases by four orders of magnitude; the specific detectivity D* of the n Bn device reduces to 1/5, and the D*of the p-i-n device decreases by over two orders of magnitude. Therefore n Bn devices are suitable to work at high temperature, which will be fit to development of high performance infrared focal plane arrays.