Open-access Sensors journal publishes a paper "Towards a Graphene-Based Low Intensity Photon Counting Photodetector" by Jamie O. D. Williams, Jack A. Alexander-Webber, Jon S. Lapington, Mervyn Roy, Ian B. Hutchinson, Abhay A. Sagade, Marie-Blandine Martin, Philipp Braeuninger-Weimer, Andrea Cabrero-Vilatela, Ruizhi Wang, Andrea De Luca, Florin Udrea, and Stephan Hofmann from University of Leicester and University of Cambridge, UK. The paper reviews graphene photodetecting approaches for visible, Terahertz and X-ray bands.
"The future applications of single photon counting photodetectors requires high detection efficiency with wavelength specificity, good temporal resolution and low dark counts. Graphene’s high mobility, tunable band gap (in bilayer graphene), strong dependence of conductivity on electric field, and other properties make it particularly suitable for this application. Here graphene acts as an (indirect) photoconductor with a high gain of transconductance due to the sharp field."