Analysis, Optimization, and Design of 2–2.8 $\mu \hbox {m}$ Stacked Multiple-Junction PIN GaInAsSb/GaSb Photodetectors for Future O/E Interconnections

The 2-2.8 μm vertically stacked multiple-junction PIN GalnAsSb/GaSb photodetectors are analyzed, optimized, and designed based on an improved general mode to predict the optimal performance of PIN infrared photodetectors arising from nonequilibrium carrier generation, diffusion, and recombination theory. Optimal thickness of intrinsic absorption region (Wopt), response quantum efficiency (RQE), detectivity (D*), and -3-dB cutoff frequency (f_{_3dB}) are calculated and optimized for a 2-2.8 μm room-temperature high-frequency operation. Ways to achieve optimal performance in practice, material, and device structures are proposed. The optimized vertically stacked multiple-junction PIN GalnAsSb/GaSb photodetector structure shows a D* of (1.6-1.9) × 10¹² cm· Hz^1/2/W,an RQE of 52%-69%, and a f_{- 3 dB} ≫ 20 GHz with W_opt = 3 μm and junction number K = 5, effective illumination area A_d = 1000 μm², and reverse bias voltage V_RB = 0.5 V. The proposed general model is validated by simulation and measurement data of fabricated single-junction detectors.