Sub-bandgap activated charges transfer in a graphene-MoS2-graphene heterostructure

Monolayers of transition metal dichalcogenides are semiconducting materials which offer many prospects in optoelectronics. A monolayer of molybdenum disulfide (MoS2) has a direct bandgap of 1.88 eV. Hence, when excited with optical photon energies below its bandgap, no photocarriers are generated an...

Full description

Saved in:
Bibliographic Details
Published inarXiv.org
Main Authors Kumar, Sunil, Singh, Arvind, Nivedan, Anand, Kumar, Sandeep, Yun, Seok Joon, Lee, Young Hee, Tondusson, Marc, Degert, Jérôme, Oberle, Jean, Freysz, Eric
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 20.03.2021
Subjects
Bandwidths
Broadband
Chalcogenides
Graphene
Heterostructures
Molybdenum disulfide
Monolayers
Optical activity
Optoelectronics
Photoexcitation
Photonic band gaps
Photons
Photovoltaic cells
Transition metal compounds
Online AccessGet full text

Cover

More Information
Summary:Monolayers of transition metal dichalcogenides are semiconducting materials which offer many prospects in optoelectronics. A monolayer of molybdenum disulfide (MoS2) has a direct bandgap of 1.88 eV. Hence, when excited with optical photon energies below its bandgap, no photocarriers are generated and a monolayer of MoS2 is not of much use in either photovoltaics or photodetection. Here, we demonstrate that large size MoS2 monolayer sandwiched between two graphene layers makes this heterostructure optically active well below the band gap of MoS2. An ultrafast optical pump-THz probe experiment reveals in real-time, transfer of carriers between graphene and MoS2 monolayer upon photoexcitation with photon energies down to 0.5 eV. It also helps to unravel an unprecedented enhancement in the broadband transient THz response of this tri-layer material system. We propose possible mechanism which can account for this phenomenon. Such specially designed heterostructures, which can be easily built around different transition metal dichalcogenide monolayers, will considerably broaden the scope for modern optoelectronic applications at THz bandwidth.
ISSN:2331-8422