Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2

Seohui Kang, Yonas Assefa Eshete, Sujin Lee, Dongyeun Won, Saemi Im, Sangheon Lee, Suyeon Cho, Heejun Yang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Tungsten disulfide (WS2) has tunable bandgaps, which are required for diverse optoelectronic device applications. Here, we report the bandgap modulation in WS2 monolayers with two-dimensional core-shell structures formed by unique growth mode in chemical vapor deposition (CVD). The core-shell structures in our CVD-grown WS2 monolayers exhibit contrasts in optical images, Raman, and photoluminescence spectroscopy. The strain and doping effects in the WS2, introduced by two different growth processes, generate PL peaks at 1.83 eV (at the core domain) and 1.98 eV (at the shell domain), which is distinct from conventional WS2 with a primary PL peak at 2.02 eV. Our density functional theory (DFT) calculations explain the modulation of the optical bandgap in our core-shell-structured WS2 monolayers by the strain, accompanying a direct-to-indirect bandgap transition. Thus, the core-shell-structured WS2 monolayers provide a practical method to fabricate lateral heterostructures with different optical bandgaps, which are required for optoelectronic applications.

Original languageEnglish
Article number103563
JournaliScience
Volume25
Issue number1
DOIs
StatePublished - 21 Jan 2022

Keywords

  • Materials science
  • Materials synthesis
  • Nanomaterials

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