High performance position-sensitive-detector based on graphene-silicon heterojunction

摘要

Position-sensitive-detectors (PSDs) based on lateral photoeffect have beenwidely used in diverse applications, including optical engineering, aerospaceand military fields. With increasing demands in long working distance, lowenergy consumption, and weak signal sensing systems, the poor responsivity ofconventional Silicon-based PSDs has become a bottleneck limiting theirapplications. Herein, we propose a high-performance passive PSD based ongraphene-Si heterostructure. The graphene is adapted as a photon absorbing andcharge separation layer working together with Si as a junction, while the highmobility provides promising ultra-long carrier diffusion length and facilitateslarge active area of the device. A PSD with working area of 8 mm x 8 mm isdemonstrated to present excellent position sensitivity to weak light at nWslevel (much better than the limit of ~{\mu}Ws of Si p-i-n PSDs). Moreimportantly, it shows very fast response and low degree of non-linearity of~3%, and extends the operating wavelength to the near infrared (IR) region(1319 and 1550 nm). This work therefore provides a new strategy for highperformance and broadband PSDs.