title: Optical Gain in MoS2 via Coupling with Nanostructured Substrate: Fabry-Perot Interference and Plasmonic Excitation.
abstract: Despite the direct band gap of monolayer transition metal dichalcogenides (TMDs), their optical gain remains limited because of the poor light absorption in atomically thin, layered materials. Most approaches to improve the optical gain of TMDs mainly involve modulation of the active materials or multilayer stacking. Here, we report a method to enhance the optical absorption and emission in MoS2 simply through the design of a nanostructured substrate. The substrate consisted of a dielectric nanofilm spacer (TiO2) and metal film. The overall photoluminescence intensity from monolayer MoS2 on the nanostructured substrate was engineered based on the TiO2 thickness and amplified by Fabry-Perot interference. In addition, the neutral exciton emission was selectively amplified by plasmonic excitations from the local field originating from the surface roughness of the metal film with spacer thicknesses of less than 10 nm. We further demonstrate that the quality factor of the device can also be engineered by selecting a spacer material with a different refractive index.
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Hye Yun
authors.initials: HY
authors.lastname: Jeong
authors.affiliation: Device Lab, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Un Jeong
authors.initials: UJ
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Gang Hee
authors.initials: GH
authors.lastname: Han
authors.affiliation: AE Group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hyangsook
authors.initials: H
authors.lastname: Lee
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Min Su
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Youngjo
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Thuc Hue
authors.initials: TH
authors.lastname: Ly
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Si Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Device Lab, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Young-Geun
authors.initials: YG
authors.lastname: Roh
authors.affiliation: Device Lab, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Won-Jae
authors.initials: WJ
authors.lastname: Joo
authors.affiliation: Device Lab, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Device Lab, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Yeonsang
authors.initials: Y
authors.lastname: Park
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) , Suwon 440-746, Republic of Korea.|Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
keywords: Fabry−Perot interference; Purcell effect; local field enhancement; molybdenum disulfide; multireflection; photoluminescence