  Position-sensitive-detectors (PSDs) based on lateral photoeffect has been
widely used in diverse applications, 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 its applications. Herein, we
present a high performance graphene based PSDs with revolutionary interfacial
amplification mechanism. Signal amplification in the order of ~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 uW 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.
