Publication Date:
2019
Description:
〈p〉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.〈/p〉
Electronic ISSN:
2375-2548
Topics:
Natural Sciences in General
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