Gate-activated photoresponse in a graphene p-n junction

Nano Lett. 2011 Oct 12;11(10):4134-7. doi: 10.1021/nl2019068. Epub 2011 Sep 12.

Abstract

We study photodetection in graphene near a local electrostatic gate, which enables active control of the potential landscape and carrier polarity. We find that a strong photoresponse only appears when and where a p-n junction is formed, allowing on-off control of photodetection. Photocurrents generated near p-n junctions do not require biasing and can be realized using submicrometer gates. Locally modulated photoresponse enables a new range of applications for graphene-based photodetectors including, for example, pixilated infrared imaging with control of response on subwavelength dimensions.