Controlling Grain Size and Continuous Layer Growth in Two-Dimensional MoS2 Films for Nanoelectronic Device Application

We report that control over the grain size and lateral growth of monolayer MoS
₂
film, yielding a uniform large-area monolayer MoS
₂
film, can be achieved by submitting the SiO
₂
surfaces of the substrates to oxygen plasma treatment and modulating substrate temperature in chemical vapor deposition (CVD) process. Scanning electron microscopy and atomic force microscopy images and Raman spectra revealed that the MoS
₂
lateral growth could be controlled by the surface treatment conditions and process temperatures. Moreover, the obtained monolayer MoS
₂
films showed excellent scalable uniformity covering a centimeter-scale SiO
₂
/Si substrates, which was confirmed with Raman and photoluminescence mapping studies. Transmission electron microscopy measurements revealed that the MoS
₂
film of the monolayer was largely single crystalline in nature. Back-gate field effect transistors based on a CVD-grown uniform monolayer MoS
₂
film showed a good current on/off ratio of ~10
⁶
and a field effect mobility of 7.23 cm
²
/V·s. Our new approach to growing MoS
₂
films is anticipated to advance studies of MoS
₂
or other transition metal dichalcogenide material growth mechanisms and to facilitate the mass production of uniform high-quality MoS
₂
films for the commercialization of a variety of applications.