The dominant ultrafast hot carrier cooling intrinsic response in the WS2/graphene heterostructure indicates its high potential for high-speed photodetection. In contrast to the intrinsic response time reflecting an inherent carrier dynamics, the extrinsic response of a photodetector includes additional effects of the device geometry (e.g. its RC time) and serves as a measure for the conventional device speed. To this end, we construct a WS2/graphene photodetector array (Figure ) via oxygen plasma etching and all-dry transfer processes (Figure and Supporting Information Section 8) and determine the extrinsic photoresponse using the experimental setup illustrated in Figure . Upon 779 nm pulse illumination (sub-WS2 bandgap), the device displays a constant response for several cycles as shown in Figure . We exemplarily extract a single pulse response and resolve it on a semi-log scale axis. The 90 to 10 photocurrent decay indicates an extrinsic response time of 7.11 ns (Figure , black curve). Using fast Fourier transformation (FFT), we calculate the electrical bandwidth under the single excitation frequency and obtain a 3-dB bandwidth of approximately 17.7 MHz (Figure ), which is comparable to that of state-of-the-art photodetectors for telecom wavelengths.