Noncontact Remote Doping for High-performance Two-dimensional Electronics

In this study, a remote doping (RD) method is proposed in which SiOx is used as the remote doping agent without directly contacting transition metal dichalcogenide (TMD) materials. It is found that a doping density as high as 1.4 × 1013 cm-2 without reducing the mobility of the doped materials can be achieved and even after 1 month later the doping concentration remained as high as 1.2 × 1013 cm-2. We observe that SiOx is able to dope several popular 2D transition metal dichalcogenides, including MoS2, WS2, and WSe2. Notably, it possesses a lower k value than that of stoichiometric silicon dioxide oxide, which is very attractive for spacer doping in terms of the perspective of circuit operation. In our experiments, MoS2 and WS2 underlap top-gate devices exhibited 10× and 200× increases in their on-currents, respectively, after being doped with SiOx. These results indicate that SiOx doping can be implemented to manufacture high-performance 2D devices.