Optoelectronic mixing with high-frequency graphene transistors
Alberto Montanaro, W. Wei, Domenico De Fazio, Ugo Sassi, Giancarlo Soavi, P. Aversa, Andrea C. Ferrari, H. Happy, P. Legagneux, Emiliano Pallecchi
Abstract
Graphene is ideally suited for optoelectronics. It offers absorption at telecom wavelengths, high-frequency operation and CMOS-compatibility. We show how high speed optoelectronic mixing can be achieved with high frequency (~20 GHz bandwidth) graphene field effect transistors (GFETs). These devices mix an electrical signal injected into the GFET gate and a modulated optical signal onto a single layer graphene(SLG) channel. The photodetection mechanism and the resulting photocurrent sign depend on theSLG Fermi level (EF). At low EF (<130 meV), a positive photocurrent is generated, while at large EF (>130 meV), a negative photobolometric current appears. This allows our devices to operate up to at least 67 GHz. Our results pave the way for GFETs optoelectronic mixers for mm-wave applications, such as telecommunications andradio/light detection and ranging(RADAR/LIDARs.).