Skip to main content
Open Access Publications from the University of California

UC Berkeley

UC Berkeley Previously Published Works bannerUC Berkeley

Intentional carbon doping reveals CH as an abundant charged impurity in nominally undoped synthetic WS2 and WSe2


Understanding the physical properties and controlling the generation of intrinsic and extrinsic defects is central to the technological adoption of 2D materials in devices. Here we identify a charged carbon-hydrogen complex at a chalcogen site (CHX) as a common, charged impurity in synthetically grown transition metal dichalcogenides (TMDs). This conclusion is drawn by comparing high resolution scanning probe microscopy measurements of nominally undoped and intentionally carbon doped TMD samples. While CH impurity densities in undoped CVD-grown WS2 and MOCVD-grown WSe2 can range anywhere from parts per million to parts per thousand, CH densities in the percentage levels were selectively generated by a post-synthetic methane plasma treatment. Our study indicates that methane plasma treatment is a selective and clean method for the controlled introduction of a charged carbon-hydrogen complex at a surface chalcogen site, a defect that is commonly present in synthetic TMDs.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View