Karl Franzens University Graz | Graz University of Technology | |
Optoelectronics with atomically thin materials Two-dimensional (2D) atomic crystals are currently receiving a lot of attention for applications in (opto-)electronics. In this talk I will review our research activities on photovoltaic energy conversion, photon detection and light emission in these materials. In particular, I will present monolayer p-n junctions, formed by electrostatic doping using a pair of split gate electrodes and MoS2/WSe2 van der Waals heterojunctions. Upon optical illumination, conversion of light into electrical energy occurs in both types of devices. I will present measurements of the electrical characteristics, the photovoltaic properties, and ultrafast measurements of the carrier dynamics. In MoS2 field effect transistors, we identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. In the second part of my talk, I will discuss studies of ultrafast photocurrent generation in graphene and applications in optical communications. We envision that the efficient photon conversion, combined with the advantages of 2D materials, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies. |