Optimal Absorber Thickness in Interband Cascade Photodetectors for High Speed Application

Interband cascade infrared photodetectors (ICIPs) have demonstrated high-temperature and high-speed operation capabilities, which shows high promising applications in free space optical communication and frequency comb spectroscopy, etc. Using a numerical model, we compared the performance of different ICIP architectures: equal-stage and current-matched ICIP architecture, along with regularillumination and reverse-illumination ICIP configurations, and optimal absorber thicknesses could be calculated under different absorption coefficients and diffusion lengths. By selecting the 90% QE point as the optimal absorber thickness, high quantum efficiency is maintained, and the shorter absorber thickness enhances bandwidth by reducing carrier transit time. This study provides valuable insights and guidance for designing high-performance ICIP.