Electrical role of sulfur vacancies in MoS2: Transient current approach

The electrical role of sulfur vacancies in MoS2 has attracted considerable attention, and numerous studies have attempted to reveal their characteristics in a donor state, an acceptor state, or a neutral state. However, there are still no definitive conclusions, and the debate continues. In this study, we investigated the effect of sulfur vacancies on the electrical properties of MoS2 using transient current measurements. After treatment with hydrazine to generate sulfur vacancies, the density of shallow traps increased by a factor of 4, whereas that of deep-level traps increased by a factor of 200. These results indicate that sulfur vacancies induce both deep- and shallow-level traps, but the trap density is higher at the deep level.