Electrical characterization of a tungsten diselenide/silicon heterostructure*

A pn diode was fabricated by using a simple method of transferring a p-type two-dimensional WSe₂ film onto a cleaved n-Si/SiO₂ wafer. The current-voltage characteristics of the device were measured, and the conduction mechanisms analyzed over a temperature range of 80 K–300 K. At high temperatures, the current-voltage characteristics of the diode show that thermionic emission transport dominates. However, tunneling also contributes at low temperatures. To explain the transport behavior of the heterojunction, a model that takes into consideration both thermionic emission and tunneling will be presented. Furthermore, the device was tested as a half-wave rectifier at room temperature at low frequencies. The rectification ratio and low turn-on voltages of the diode make it suitable for optoelectronic applications.