Theoretical analysis of the detectivity in N-p and P-n GaSb/GaInAsSb infrared photodetectors

In this paper, the detectivity as well as the quantum efficiency and the ze ro-bias resistance-area product in N-p and P-n GaSb/Ga0.8In0.2As0.19Sb0.81 infrared detectors is analyzed, based on the incident wavelength and the pa rameters of GaSb and Ga0.8In0.2As0.19Sb0.81. The results show that the dete ctivity for the N-p structure is much higher than that for the P-n structur e. In addition, the tunneling mechanism in both heterostructures strongly d ecreases the performance of Ga0.8In0.2As0.Sb-19(0.81)/GaSb detectors. The o ptimum detectivity is obtained when the zero-bias resistance-area product i s limited by the generation-recombination mechanism. Furthermore, the detec tivity in the N-p heterostructure is saturated with a small thickness of p- Ga0.8In0.2As0.19Sb0.81 while the one in the P-n heterostructure is maximum with the thickness of n-Ga0.8In0.2As0.19Sb0.81 in the range of 2.5-3 mu m.