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

iScience

Heejun Yang¹  Sujin Lee²  Sangheon Lee²  Saemi Im²  Suyeon Cho²  Seohui Kang²  Yonas Assefa Eshete³  Dongyeun Won³ 

[1] Corresponding author;Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea;Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea;

关键词: Materials science;    Materials synthesis;    Nanomaterials;   

DOI  :  

来源: DOAJ

【 摘 要 】

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 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.

【 授权许可】

Unknown