Emerging Single‐Photon Detectors Based on Low‐Dimensional Materials

Abstract Single‐photon detectors (SPDs) that can sense individual photons are the most sensitive instruments for photodetection. Established SPDs such as conventional silicon or III–V compound semiconductor avalanche diodes and photomultiplier tubes have been used in a wide range of time‐correlated photon‐counting applications, including quantum information technologies, in vivo biomedical imaging, time‐of‐flight 3D scanners, and deep‐space optical communications. However, further development of these fields requires more sophisticated detectors with high detection efficiency, fast response, and photon‐number‐resolving ability, etc. Thereby, significant efforts have been made to improve the performance of conventional SPDs and to develop new photon‐counting technologies. In this review, the working mechanisms and key performance metrics of conventional SPDs are first summarized. Then emerging photon‐counting detectors (in the visible to infrared range) based on 0D quantum dots, 1D quantum nanowires, and 2D layered materials are discussed. These low‐dimensional materials exhibit many exotic properties due to the quantum confinement effect. And photodetectors built from these n D‐materials ( n = 0, 1, 2) can potentially be used for ultra‐weak light detection. By reviewing the status and discussing the challenges faced by SPDs, this review aims to provide future perspectives on the research directions of emerging photon‐counting technologies.