H$_2$ exposure induced structural and electrical modulation in MoS$_2$

We have demonstrated the structural modulation at the edge of MoS$_2$ due to H$_2$ exposure with spatially resolved Raman spectroscopy and the electrical characteristics of few-layer MoS$_2$ with respect to H$_2$ pressure from vacuum to 20 bars at 295 K \textless\ $T$ \textless\ 350 K. Upon H$_2$ exposure, the significant change of the edge in E$_{\mathrm{2g}}$ mode was observed. The conductance increases and threshold voltage ($V_{th})$ shifts toward a negative gate voltage region, indicating n-type doping. These behaviors are enhanced by high temperature and long exposure time ($t)$. The results reveal the creation of vacancy at the edge sites of MoS$_2$ in H$_2$ atmosphere causing the enhancement of $n$-type doping due to increase of metallic region.