Carbon doping of WS<sub>2</sub> monolayers: Bandgap reduction and p-type doping transport.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31139746.
- Also identified by DOI 10.1126/sciadv.aav5003 and PMC identifier 6534391.
- Licence recorded as CC BY-NC.
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Abstract
Chemical doping constitutes an effective route to alter the electronic, chemical, and optical properties of two-dimensional transition metal dichalcogenides (2D-TMDs). We used a plasma-assisted method to introduce carbon-hydrogen (CH) units into WS<sub>2</sub> monolayers. We found CH-groups to be the most stable dopant to introduce carbon into WS<sub>2</sub>, which led to a reduction of the optical bandgap from 1.98 to 1.83 eV, as revealed by photoluminescence spectroscopy. Aberration corrected high-resolution scanning transmission electron microscopy (AC-HRSTEM) observations in conjunction with first-principle calculations confirm that CH-groups incorporate into S vacancies within WS<sub>2</sub>. According to our electronic transport measurements, undoped WS<sub>2</sub> exhibits a unipolar n-type conduction. Nevertheless, the CH-WS<sub>2</sub> monolayers show the emergence of a p-branch and gradually become entirely p-type, as the carbon doping level increases. Therefore, CH-groups embedded into the WS<sub>2</sub> lattice tailor its electronic and optical characteristics. This route could be used to dope other 2D-TMDs for more efficient electronic devices.