Graphene photo-transistors with ultra-high gain
Description of Activities:
Graphene is an attractive material for optoelectronics and photodetection applications because it offers a broad spectral bandwidth and fast response times. However, the responsivity of bare graphene photoresponse is limited due to weak absorption and the absence of gain.
Here, we develop hybrid graphene-semiconductor composites to enhance photodetection sensitivity and to introduce photodetection gain. Recently, we demonstrated a gain of 108 electrons per photon and a responsivity of 107 A/W in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of colloidal quantum dots. In addition, we have found that graphene is a promising material for highly efficient broadband extraction of light energy into electronic degrees of freedom, enabling a new class of high-efficiency optoelectronic and photovoltaic applications.
Currently, we are further improving speed, sensitivity and large-scale fabrication in order to develop sensors and cameras for infrared frequencies.