Reduced interface effect of proton beam irradiation on the electrical properties of WSe 2 /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 2 ) channels and hexagonal boron-nitride (hBN)/SiO 2 gate dielectrics. The electrical characteristics of WSe 2 FETs were measured before and after the irradiation at various proton beam doses of 10 13 , 10 14 , and 10 15 cm -2 . In particular, we demonstrated the dependence of proton irradiation-induced effects on hBN layer thickness in WSe 2 FETs. We observed that the hBN layer reduces the WSe 2 /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 WSe 2 channel and SiO 2 dielectric by the hBN interlayer prevents the interface effects originating from the irradiation-induced positive trapped charges in SiO 2 reaching the interface. This work will help improve our understanding of the interface effect of high-energy irradiation on TMDC-based nanoelectronic devices.