Versatile Electronic Devices Based on WSe 2 /SnSe 2 Vertical van der Waals Heterostructures.

Van der Waals heterostructures formed by stacking of various two-dimensional materials are promising in electronic applications. However, the performances of most reported electronic devices based on van der Waals heterostructures are far away from those of existing (Si, Ge, and III-V bulk material based) technologies. Here, we report high-performance heterostructure devices based on vertically stacked tungsten diselenide and tin diselenide. Due to the unique band alignment and the atomic thickness of the material, both charge carrier transport and energy barrier can be effectively modulated by the applied electrical field. As a result, the heterostructure devices show superb characteristics, with a high current on/off ratio of ∼3 × 10 ⁸ , an average subthreshold slope of 126 mV/dec over 5 dec of current change due to band-to-band tunneling, an ultrahigh rectification ratio of ∼3 × 10 ⁸ , and a current density of more than 10 ⁴ A/cm ² . Furthermore, a small signal half-wave rectifier circuit based on a majority-carrier-transport-dominated diode is successfully demonstrated, showing great potential in future high-speed electronic applications.