Photoresponsivity enhancement in monolayer MoS2 by rapid O2:Ar plasma treatment

We report up to ten-fold enhancement of the photoresponsivity of monolayer molybdenum disulfide (MoS2) by treatment with O2:Ar (1:3) plasma. We characterize the surface of plasma-exposed MoS2 by TEM, Raman, and PL mapping and discuss the role of MoOx in improving the photocurrent generation in our devices. At the highest tested laser power of 0.1 mW, we find ten-fold enhancements to both the output current and carrier field-effect mobility at the illumination wavelength of 488 nm. We suggest that the improvement of electrical performance is due to the surface presence of MoOx resulting from the chemical conversion of MoS2 by the oxygen-containing plasma. Our results high-light the beneficial role of plasma treatment as a fast and convenient way of improving the properties of synthetic 2D MoS2devices for future consideration in optoelectronics research