Tuning Transport and Photoelectric Performance of Monolayer MoS₂ Device by E-Beam Irradiation

Here, the effect of E-beam irradiation on the transport properties of the monolayer MoS₂ is investigated in situ using scanning electron microscope (SEM). The results show that the source drain current is increased under E-beam irradiation; the current gradually increases to a saturation value with an increase in irradiation time, and the saturation value increases with an increase in E-beam intensity. After E-beam irradiation, X-ray photoelectron spectroscopy (XPS) results show that the stoichiometry of MoS₂ is modified, while the Raman and PL results reveal that the optical performance of the monolayer MoS₂ is not deteriorated. The source–drain current and electron mobility of the MoS₂ transistor are reduced by E-beam irradiation, while the on–off current ratio of the transistor almost unchanges. However, the photoresponse performance, such as the light dark current ratio, response, and release speed of the device are improved. The results are discussed by the creation of defects which vary the injected and trapped charges of the sample by E-beam irradiation. The results provide a new method to improve the optoelectronic performance of two dimensional (2D) materials devices.