The Effect of Period Number and Blocking Layer Thickness on Superlattice Infrared Photodetector

The recent development of infrared photodetector tends to reduce the dark current and also the power consumption. Because of the miniband structure, superlattice is a good choice to implement the low power consumption detector array. Unlike quantum well infrared photodetector, a blocking layer is needed to reduce the unintentional dark current. The blocking layer thickness not only affects the electron transport but also the operation bias range. In this paper, we have investigated the effect of changing the blocking layer thickness and the period number of superlattice. Superlattice with few periods is ideal for low bias applications because of the high group velocity. The thin blocking layer allows more electrons to transport through it under the same electric field magnitude but higher dark current is also expected. Therefore, the thin blocking layer sample is suitable for the broadband response under low bias while the higher dark current is the disadvantage for high temperature applications.