Fast THz Detection by an Asymmetric-Dual-Grating-Gate Graphene-Channel FET Based on Plasmonic and Photothermoelectric Effects

We investigate the fast photoresponse of an asymmetric dual-grating-gate graphene-channel field effect transistor (FET) terahertz (THz) detector and experimentally demonstrate a 10 -ps-order fast response time to 0.95-THz radiation incidence at room temperature. Through the experimentally obtained bias-voltage dependences of the photoresponse, we identify that both plasmonic and photothermoelectric rectification effects coexist in a wide gate bias voltage range as the THz detection mechanisms.