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

Nano Select

Eric Freysz¹  Marc Tondusson¹  Jérôme Degert¹  Jean Oberle¹  Young Hee Lee²  Seok Joon Yun²  Anand Nivedan³  Sandeep Kumar³  Arvind Singh³  Sunil Kumar³ 

[1] CNRS, LOMA UMR 5798 Univ. Bordeaux Talence 33405 France;Department of Energy Science Sungkyunkwan University (SKKU) Suwon 16419 Republic of Korea;Femtosecond Spectroscopy and Nonlinear Photonics Laboratory Department of Physics Indian Institute of Technology Delhi New Delhi 110016 India;

关键词: carrier dynamics;    graphene;    heterostructures;    terahertz;    transition metal dichalcogenides;    ultrafast detector;   

DOI  :  10.1002/nano.202000159

来源: DOAJ

【 摘 要 】

Abstract 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.

【 授权许可】

Unknown