A comprehensive study on the effects of gamma radiation on the physical properties of a two-dimensional WS2 monolayer semiconductor

This article reports the effects of gamma radiation on the structural, optical and magnetic properties of monolayer tungsten disulfide (WS2) grown by a scalable van der Waals epitaxial (VdWE) process on a SiO2 coated Si substrate. We found that ionizing radiation (gamma ray) interacts strongly with two-dimensional WS2, which induces effective p-doping in the samples. As the radiation dose increases, the p-doping concentration increases substantially. In addition, in the small radiation dose regime, the WS2 monolayers exhibit usual diamagnetic behavior. However, a remarkable ferromagnetic hysteresis emerges when the WS2 monolayer is irradiated with 400 Gys. This is attributed to the presence of irradiation-induced complex vacancies composed of one tungsten and a pair of its nearby sulfurs. Moreover, these results have shown that the detector based on the large scale monolayer VdWE-grown two-dimensional WS2 is an appealing candidate for sensing high-energy photons at small radiation doses.