Approaching the Quantum Limit of Photodetection in Solid-State Photodetectors

Many aspects of life involve sensitive photodetection, which is now widely implemented in solid-state devices made from semiconductor materials due to their relatively low cost, high scalability, and better compatibility with the existing CMOS technology. State-of-the-art Geiger-mode avalanche detectors and the challenges they faced in single-photon detection efficiency and timing resolution are covered. Emerging classes of solid-state detectors are then reviewed, including bandgap engineering and the use of a heavily doped emitter. A novel class of detector is introduced exhibiting monolithic incorporation of impact ionization and bipolar gain in a single device structure by using bandgap engineering. Finally, we discuss a recent detector concept which involves using disorder in solid-state material to substantially increase the probability of carrier excitation and reduce noise. The recent breakthroughs in solid-state photodetection can significantly impact areas of quantum information processing, optic communications, and imaging.