To further improve the performance of graphene/TMDC heterostructures based on the ultrafast hot carrier extraction and cooling, we fabricate a vertical WS2/graphene/WSe2 heterostructure (Figure and). In 2PC measurements (Supporting Information Section 9), the device demonstrates an intrinsic charge carrier dynamics similar to that in the sample WS2/graphene heterostructure, indicating the same photo-thermionic detection process. In the corresponding SPCM experiment (Figure ) the photocurrent appears at the heterostructure region, proving the contribution of hot carriers from the graphene. The advantage of this new heterostructure is an additional vertical built-in electric field manifesting in the rectifying transport behavior displayed in Figure and an on-off ratio of 3500, much higher than that of the lateral device. Furthermore, we obtain a laser-frequency independent extrinsic response time of approximately 1.71 ns (Figure ) and a 3-dB bandwidth of 123.4 MHz (Figure ) at 779 nm laser excitation. Thus, the vertical WS2/graphene/WSe2 heterostructure synergistically combines the properties of photodetectors with sole hot carrier injection and that of devices with built-in electric field.