High-Speed Mid-Infrared Interband Cascade Photodetector Based on InAs/GaAsSb Type-II Superlattice

High-speed mid-wave infrared (MWIR) photodetectors have applications in the areas such as free space optical communication and frequency comb spectroscopy. However, most of the research on the MWIR photodetectors have been focused on how to increase the quantum efficiency and reduce the dark current, in order to improve the detectivity (D
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), and the 3 dB bandwidth performance of the corresponding MWIR photodetectors is still not fully studied. In this work, we report and characterize a MWIR interband cascade photodetector based on InAs/GaAsSb type-II superlattice with a 50% cutoff wavelength at ∼5.3 μm at 300 K. The 3 dB cutoff frequency is 2.4 GHz at 300 K, for a 40 μm circular diameter device under −5 V applied bias. Limitations on the detector high-speed performance are also discussed.