Effects of energetic ion irradiation on WSe(2)/SiC heterostructures

The remarkable electronic properties of layered semiconducting transition metal dichalcogenides (TMDs) make them promising candidates for next-generation ultrathin, low-power, high-speed electronics. It has been suggested that electronics based upon ultra-thin TMDs may be appropriate for use in high radiation environments such as space. Here, we present the effects of irradiation by protons, iron, and silver ions at MeV-level energies on a WSe(2)/6H-SiC vertical heterostructure studied using XPS and UV-Vis-NIR spectroscopy. It was found that with 2 MeV protons, a fluence of 10(16) protons/cm(2) was necessary to induce a significant charge transfer from SiC to WSe(2), where a reduction of valence band offset was observed. Simultaneously, a new absorption edge appeared at 1.1 eV below the conduction band of SiC. The irradiation with heavy ions at 10(16) ions/cm(2) converts WSe(2) into a mixture of WO(x) and Se-deficient WSe(2). The valence band is also heavily altered due to oxidation and amorphization. However, these doses are in excess of the doses needed to damage TMD-based electronics due to defects generated in common dielectric and substrate materials. As such, the radiation stability of WSe(2)-based electronics is not expected to be limited by the radiation hardness of WSe(2), but rather by the dielectric and substrate.