This paper demonstrates the fabrication and operation of a vertically integrated phototransistor based on single‐layer MoS2/multilayer WSe2 van der Waals heterojunction. Under the gate modulation effects, the device which combines advantages of their constituents displays a novel feature in the transfer characteristics where a current peak appears at small gate voltage bias and exhibits excellent optical broadband photodetecting properties. Upon visible light illumination (660 nm), the photodetection capabilities reach the optimal values simultaneously with the photoresponsivity of 17.8 A W−1, photosensivity of 140, and the response speed of <80 ms. The device also shows good photoresponse under near‐infrared light illumination (850 nm) and the obvious dependence on the gate voltage which plays a switching role for near infrared light photodetection. This 2D heterostructured broadband photodetector may provide an available device structure for an essential sensing component in the future wearable electronics applications.

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As-doped p-type ZnO films were grown on GaAs by sputtering and thermal diffusion process. Hall effect measurements showed that the as-grown films were of n-type conductivity and they were converted to p-type behavior after thermal annealing. Moreover, the hole concentration of As-doped p-type ZnO was very impressible to the oxygen ambient applied during the annealing process. In addition, the bonding state of As in the films was investigated by x-ray photoelectron spectroscopy. This study not only demonstrated an effective method for reliable and reproducible p-type ZnO fabrication but also helped to understand the doping mechanism of As-doped ZnO.