WSe2 2D p‐type semiconductor‐based electronic devices for information technology: Design, preparation, and applications

The pioneering exfoliation of monolayer tungsten diselenide has greatly inspired researchers toward semiconducting applications. WSe2 belongs to a family of transition‐metal dichalcogenides. Similar to graphene, WSe2 and analogous dichalcogenides have layered structures with weak van der Waals interactions between two adjacent layers. First, the readers are presented with the fundamentals of WSe2, such as types, morphologies, and properties. Here, we report the characterization principles and practices such as microscopy, spectroscopy, and diffraction. Second, the methods for obtaining high‐quality WSe2, such as exfoliation, hydrothermal and chemical vapor deposition, are briefly listed. With advantages of light weight, flexibility, and high quantum efficiency, 2D materials may have a niche in optoelectronics as building blocks in p‐n junctions. Therefore, we introduce a state‐of‐the‐art demonstration of heterostructure devices employing the p‐type WSe2 semiconductor. The device architectures include field‐effect transistors, photodetectors, gas sensors, and photovoltaic solar cells. Due to its unique electronic, optical, and energy band properties, WSe2 has been increasingly investigated due to the conductivity of the p‐type charge carrier upon palladium contact. Eventually, the dynamic research on WSe2 and van der Waals heterostructures is summarized to arouse the passion of the 2D research community. The scheme of structure, properties, and applications of WSe2. The review article contains a brief introduction of WSe2, including its properties, preparation, and electronic device applications. WSe2 has an MX2 atomic configuration, a 1.6 eV energy bandgap (monolayer), and can be prepared by mechanical exfoliation, chemical vapor deposition, and hydrothermal methods. Basic devices are introduced, including photodetectors, gas sensors, and field‐effect transistors. Eventually, readers are presented with novel information devices, such as light‐emitting diodes, rectifiers, logic inverters, CMOS circuits, piezotronics, and piezophototronics.