Wafer scale quasi single crystalline $MoS_{2}$ realized by epitaxial phase conversion

Xiangming Xu, Zhenwei Wang, Sergei Lopatin, M A Quevedo-Lopez, Husam N. Alshareef

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Vapor-solid phase reaction (VSPR) is a two-step process for synthesizing 2D MoS2. In the first step, a precursor film such as molybdenum oxide is grown on a substrate, followed by a sulfurization process at elevated temperature. This process offers a scalable fabrication of wafer-scale film with feasible control in thickness and uniformity. However, the properties of MoS2 films from this VSPR process often suffer from poor electrical properties. The major reason is their polycrystalline (PC) structure with large concentrations of defects and grain boundaries, which are inherited from the amorphous precursor films. Here, we report a new and scalable VSPR process in which epitaxial MoO2 films (grown over a 2-inch wafers) are used as high-quality precursors, which are converted into quasi-single-crystalline (QSC) MoS2. We demonstrate that the field effect mobility of transistors fabricated using a QSC MoS2 channel is almost 35 times larger, compared to a PC MoS2 channel, also better than most previously reported MoS2 films by other two-step MoS2 formation processes. Our process presents a new approach in which the epitaxial growth of the precursor phase can be used to improve 2D semiconductor and device performance.
Original languageEnglish (US)
Pages (from-to)015030
Journal2D Materials
Issue number1
StatePublished - Dec 17 2018

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST). The authors thank Dr. Yao He and Dr. Xiaohe Miao for their help in the XRD measurement, Ms. Nini Wei for her help in the TEM sample preparation by FIB, Dr. Dalaver H. Anjum for the TEM measurement of the cross-section structure of the samples, and Dr. Mohamed Nejib Hedhili for help with the XPS measurements.


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