Fabrication and Research of High Speed and High Saturation Mid-wave Interband Cascade Infrared Photodetectors

Antimony-based superlattice (SL) interband cascade photodetectors (ICIPs) have shown great potential for mid-infrared high-frequency systems. However, the multiple-stage architecture that benefits high speed operation is one of the main factors hampering the device optical output performance. Here, we demonstrate the fabrication, characterization, and analysis of a current-matched high-speed ICIP based on InAs/GaSb type-II SLs. Optimized multiple-stage architecture enhances incident photons utilization efficiency. Carefully designed electrode structures reduce the parasitic RC time constant. The fabricated ICIP achieves a 7.16 GHz 3dB bandwidth at -2.7 V with a saturation output current of 6.78 mA. These results validate the potential of ICIPs to achieve both high-capacity signal output and fast response, providing a technical foundation for emerging fields such as mid-infrared communications, autonomous driving sensing, and beyond.