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 zero-bias resistance-area product in N-p and P-n GaSb/Ga_0.8 In_0.2As_0.19Sb_0.81 infrared detectors is analyzed, based on the incident wavelength and the parameters of GaSb and Ga_0.8In_0.2As_0.19Sb_0.81. The results show that the detectivity for the N-p structure is much higher than that for the P-n structure. In addition, the tunneling mechanism in both heterostructures strongly decreases the performance of Ga_0.8 In_0.2As_0.19Sb_0.81/GaSb detectors, The optimum detectivity is obtained when the zero-bias resistance-area product is limited by the generation-recombination mechanism. Furthermore, the detectivity in the N-p heterostructure is saturated with a small thickness of p-Ga_0.8In_0.2As_0.19 Sb_0.81 while the one in the P-n heterostructure is maximum with thickness of n-Ga_0.8In_0.2As_0.19 Sb_0.81 in the range of 2.5-3 μm