Interfacial amplification for graphene-based position-sensitive-detectors

Position-sensitive-detectors (PSDs) based on lateral photoeffect have been widely used in diverse applications(1-9), including optical engineering, aerospace and military fields. With increasing demand in long distance, low energy consumption, and weak signal sensing systems, the poor responsivity of conventional PSDs has become a bottleneck limiting their applications, for example, silicon p-n or p-i-n junctions(2-5), or other materials and architectures(6-10). Herein, we present a high-performance graphene-based PSDs with revolutionary interfacial amplification mechanism. Signal amplification in the order of similar to 10(4) has been demonstrated by utilizing the ultrahigh mobility of graphene and long lifetime of photo-induced carriers at the interface of SiO2/Si. This would improve the detection limit of Si-based PSDs from mu W to nW level, without sacrificing the spatial resolution and response speed. Such interfacial amplification mechanism is compatible with current Si technology and can be easily extended to other sensing systems(11,12).