Strain-Induced Indirect to Direct Bandgap Transition in Multilayer WSe 2
University of California, Berkeley · Lawrence Berkeley National Laboratory · +1 more institution
Abstract
Transition metal dichalcogenides, such as MoS2 and WSe2, have recently gained tremendous interest for electronic and optoelectronic applications. MoS2 and WSe2 monolayers are direct bandgap and show bright photoluminescence (PL), whereas multilayers exhibit much weaker PL due to their indirect optical bandgap. This presents an obstacle for a number of device applications involving light harvesting or detection where thicker films with direct optical bandgap are desired. Here, we experimentally demonstrate a drastic enhancement in PL intensity for multilayer WSe2 (2-4 layers) under uniaxial tensile strain of up to 2%. Specifically, the PL intensity of bilayer WSe2 is amplified by ∼ 35× , making it comparable to…
Citation impact
- FWCI
- 19.58
- Percentile
- 100%
- References
- 30
Authors
9- SBSujay B. DesaiCorresponding
University of California, Berkeley, Lawrence Berkeley National Laboratory
- GSGyungseon Seol
University of Florida
- JSJeong Seuk Kang
University of California, Berkeley, Lawrence Berkeley National Laboratory
- HFHui Fang
Lawrence Berkeley National Laboratory, University of California, Berkeley
- CBCorsin Battaglia
University of California, Berkeley, Lawrence Berkeley National Laboratory
Topics & keywords
- Band gap
- Photoluminescence
- Materials science
- Monolayer
- Bilayer
- Direct and indirect band gaps
- Optoelectronics
- Density functional theory
- Affordable and clean energy