조수연 (Suyeon Cho) 교수님의 연구 Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2가 iScience에 출판되었습니다. 축하드립니다!
Journal DOI: https://doi.org/10.1016/j.isci.2021.103563
SUMMARY
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 the-
ory (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.
