Reduced interface effect of proton beam irradiation on the electrical properties of WSe/hBN field effect transistors.

Two-dimensional transition metal dichalcogenide (TMDC) semiconductors are emerging as strong contenders for electronic devices that can be used in highly radioactive environments such as outer space where conventional silicon-based devices exhibit nonideal characteristics for such applications. To address the radiation-induced interface effects of TMDC-based electronic devices, we studied high-energy proton beam irradiation effects on the electrical properties of field-effect transistors (FETs) made with tungsten diselenide (WSe) channels and hexagonal boron-nitride (hBN)/SiOgate dielectrics. The electrical characteristics of WSeFETs were measured before and after the irradiation at various proton beam doses of 10, 10, and 10cm. In particular, we demonstrated the dependence of proton irradiation-induced effects on hBN layer thickness in WSeFETs. We observed that the hBN layer reduces the WSe/dielectric interface effect which would shift the transfer curve of the FET toward the positive direction of the gate voltage. Also, this interface effect was significantly suppressed when a thicker hBN layer was used. This phenomenon can be explained by the fact that the physical separation of the WSechannel and SiOdielectric by the hBN interlayer prevents the interface effects originating from the irradiation-induced positive trapped charges in SiOreaching the interface. This work will help improve our understanding of the interface effect of high-energy irradiation on TMDC-based nanoelectronic devices.