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/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ infrared detectors is analyzed, based on the incident wavelength and the parameters of GaSb and Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 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/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 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/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ while the one in the P-n heterostructure is maximum with thickness of n-Ga/sub 0.8/In/sub 0.2/As/sub 0.19/Sb/sub 0.81/ in the range of 2.5-3 /spl mu/m.