Ultrasensitive graphene‐Si position‐sensitive detector for motion tracking.

Motion tracking has attracted great attention in the fields of real‐time tracking, nanorobotics, and targeted therapy. For achieving more accurate motion tracking, the highly sensitive position‐sensitive detector (PSD) is desirable. Here, we demonstrate a meliorated PSD based on graphene‐Si heterojunction for motion tracking. The position sensitivity of PSD was improved by employing surface engineering of graphene. Through modulating the transport property of graphene, nearly 20‐fold increase of sensitivity was achieved under weak light, and at the same time, the detection limit power was reduced to ~ 2 nW. A motion tracking system was developed based on the improved PSD, and human arm swing was tracked, which demonstrated high sensitivity and real‐time tracking capabilities of the PSD. In addition, the PSD can support up to ~ 10 kHz high‐frequency tracking. This work provides a new strategy for improving the performance of PSD, and promotes the development of two‐dimensional materials in novel optoelectronic devices. [ABSTRACT FROM AUTHOR]