Authors: Xiangming Xu, Chenhui Zhang, Mrinal K. Hota, Zhixiong Liu, Xixiang Zhang, Husam N. Alshareef
Published: 2020-01-21
Source: Full article
AbstractWafer‐scale, single‐crystalline 2D semiconductors without grain boundaries and defects are needed for developing reliable next‐generation integrated 2D electronics. Unfortunately, few literature reports exist on the growth of 2D semiconductors with single‐crystalline structure at the wafer scale. It is shown that direct sulfurization of as‐deposited epitaxial MoO2 films (especially, with thicknesses more than ≈5 nm) produces textured MoS2 films. This texture is inherited from the high density of defects present in the as‐prepared epitaxial MoO2 film. In order to eliminate the texture of the converted MoS2 films, a new capping layer annealing process (CLAP) is introduced to improve the crystalline quality of as‐deposited MoO2 films and minimize its defects. It is demonstrated that sulfurization of the CLAP‐treated MoO2 films leads to the formation of single‐crystalline MoS2 films, instead of textured films. It is shown that the single‐crystalline MoS2 films exhibit field‐effect mobility of 6.3 cm2 V−1 s−1, which is 15 times higher than that of textured MoS2. These results can be attributed to the smaller concentration of defects in the single‐crystalline films.