Indirect Bandgap Puddles in Monolayer MoS2 by Substrate-Induced Local Strain

Bong Gyu Shin; Gang Hee Han; Seok Joon Yun; Hye Min Oh; Jung Jun Bae; Young Jae Song; Chong-Yun Park; Young Hee Lee

doi:10.1002/adma.201602626

Indirect Bandgap Puddles in Monolayer MoS₂ by Substrate-Induced Local Strain

Adv Mater. 2016 Nov;28(42):9378-9384. doi: 10.1002/adma.201602626. Epub 2016 Sep 7.

Authors

Bong Gyu Shin^{1

2}, Gang Hee Han^{1

2}, Seok Joon Yun^{1

3}, Hye Min Oh^{1

3}, Jung Jun Bae^{1

3}, Young Jae Song^{1

4

5}, Chong-Yun Park⁴, Young Hee Lee^{1

3

4}

Affiliations

¹ Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon, 16419, South Korea.
² Sungkyunkwan University, Suwon, 16419, South Korea.
³ Department of Energy Science, Sungkyunkwan University, Suwon, 16419, South Korea.
⁴ Department of Physics, Sungkyunkwan University, Suwon, 16419, South Korea.
⁵ Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 16419, South Korea.

PMID: 27601145
DOI: 10.1002/adma.201602626

Abstract

An unusually large bandgap modulation of 1.23-2.65 eV in monolayer MoS₂ on a SiO₂ /Si substrate is found due to the inherent local bending strain induced by the surface roughness of the substrate, reaching the direct-to-indirect bandgap transition. Approximately 80% of the surface area reveals an indirect bandgap, which is confirmed further by the degraded photoluminescence compared to that from suspended MoS₂ .

Keywords: MoS2; bandgap; direct-to-indirect bandgap transition; layered materials; strain.