Carbon doping of WS2 monolayers: Bandgap reduction and p-type doping transport

Fu Zhang, Yanfu Lu, Daniel S. Schulman, Tianyi Zhang, Kazunori Fujisawa, Zhong Lin, Yu Lei, Ana LauraElias, Saptarshi Das, Susan B. Sinnott, Mauricio Terrones

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Abstract

Chemical doping constitutes an effective route to alter the electronic, chemical, and optical properties of twodimensional transition metal dichalcogenides (2D-TMDs). We used a plasma-assisted method to introduce carbon-hydrogen (CH) units into WS2 monolayers. We found CH-groups to be the most stable dopant to introduce carbon into WS2, 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 WS2. According to our electronic transport measurements, undoped WS2 exhibits a unipolar n-type conduction. Nevertheless, the CH-WS2 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 WS2 lattice tailor its electronic and optical characteristics. This route could be used to dope other 2D-TMDs for more efficient electronic devices.

Original languageEnglish (US)
Article numberaav5003
JournalScience Advances
Volume5
Issue number5
DOIs
StatePublished - Jan 1 2019

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)
  • General

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