Reduced interface effect of proton beam irradiation on the electrical properties of WSe₂/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 (WSe₂) channels and hexagonal boron-nitride (hBN)/SiO₂gate dielectrics. The electrical characteristics of WSe₂FETs were measured before and after the irradiation at various proton beam doses of 10¹³, 10¹⁴, and 10¹⁵cm^-2. In particular, we demonstrated the dependence of proton irradiation-induced effects on hBN layer thickness in WSe₂FETs. We observed that the hBN layer reduces the WSe₂/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 WSe₂channel and SiO₂dielectric by the hBN interlayer prevents the interface effects originating from the irradiation-induced positive trapped charges in SiO₂reaching the interface. This work will help improve our understanding of the interface effect of high-energy irradiation on TMDC-based nanoelectronic devices.