摘要：SummaryTungsten disulfide (WS2) has tunable bandgaps, which are required for diverse optoelectronic device applications. Here, we report the bandgap modulation in WS2monolayers with two-dimensional core-shell structures formed by unique growth mode in chemical vapor deposition (CVD). The core-shell structures in our CVD-grown WS2monolayers 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 WS2with 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 WS2monolayers by the strain, accompanying a direct-to-indirect bandgap transition. Thus, the core-shell-structured WS2monolayers provide a practical method to fabricate lateral heterostructures with different optical bandgaps, which are required for optoelectronic applications.Graphical abstractDisplay OmittedHighlights•Core-shell-structured WS2monolayers with modulated bandgap are grown by CVD•Doping and strain effect in band structure are revealed by Raman and PL spectroscopy•Through DFT calculation, we showed that the bandgap can be tuned by the strain•Core-shell-structured WS2with different bandgap provides option to tune the bandgapMaterials science; Materials synthesis; Nanomaterials
