Stability of semiconducting transition metal dichalcogenides irradiated by soft X-rays and low energy electrons

Semiconducting two-dimensional materials (2DMs) such as molybdenum disulfide and tungsten diselenide have attracted significant attention due to their unique electronic properties. Understanding their nanoscale radiation tolerance is needed for developing radiation-hardened nanoelectronics. Here, we report that the XPS environment of soft X-ray (E = 1.486 keV) exposure in a vacuum combined with a low energy electron flood gun leads to charge accumulation in the 2D layers over time, with little impact on layer chemistry. Additionally, the charging that induced the 2DM/substrate heterostructure depends more on the growth technique, the size of as-grown domains, and the surface coverage of the 2DM than the conductivity of the substrate. Charging is minimized for the combination of a continuous 2DM film and strong coupling between the 2DM and the substrate.