Abstract
We demonstrate 230 MHz photodetection and a switching energy of merely 27 fJ using WSe(2) multilayers and a very simple device architecture. This improvement over previous, slower WSe(2) devices is enabled by systematically reducing the RC constant of devices through decreasing the photoresistance and capacitance. In contrast to MoS(2), reducing the WSe(2) thickness toward a monolayer only weakly decreases the response time, highlighting that ultrafast photodetection is also possible with atomically thin WSe(2). Our work provides new insights into the temporal limits of pure transition metal dichalcogenide photodetectors and suggests that gigahertz photodetection with these materials should be feasible.