Stability of the tungsten diselenide and silicon carbide heterostructure against high energy proton exposure

摘要

Single layers of tungsten diselenide (WSe_2) can be used to construct ultra-thin, high-performance electronics. Additionally, there has been considerable progress in controlled and direct growth of single layers on various substrates. Based on these results, high-quality WSe_2-based devices that approach the limit of physical thickness are now possible. Such devices could be useful for space applications, but understanding how high-energy radiation impacts the properties of WSe_2 and the WSe_2/substrate interface has been lacking. In this work, we compare the stability against high energy proton radiation of WSe_2 and silicon carbide (SiC) heterostructures generated by mechanical exfoliation of WSe_2 flakes and by direct growth of WSe_2 via metal-organic chemical vapor deposition (MOCVD). These two techniques produce WSe_2/SiC heterostructures with distinct differences due to interface states generated during the MOCVD growth process. This difference carries over to differences in band alignment from interface states and the ultra-thin nature of the MOCVD-grown material. Both heterostructures are not susceptible to proton-induced charging up to a dose of 10~(16) protons/cm~2, as measured via shifts in the binding energy of core shell electrons and a decrease in the valence band offset. Furthermore, the MOCVD-grown material is less affected by the proton exposure due to its ultra-thin nature and a greater interaction with the substrate. These combined effects show that the directly grown material is suitable for multi-year use in space, provided that high quality devices can be fabricated from it.