Pressure-dependent optical and vibrational properties of monolayer molybdenum disulfide
AuthorsNayak, Avinash P.
Moran, Samuel T.
Chhowalla, Manish U.
Singh, Abhishek Kumar
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Permanent link to this recordhttp://hdl.handle.net/10754/564009
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AbstractControlling the band gap by tuning the lattice structure through pressure engineering is a relatively new route for tailoring the optoelectronic properties of two-dimensional (2D) materials. Here, we investigate the electronic structure and lattice vibrational dynamics of the distorted monolayer 1T-MoS2 (1T′) and the monolayer 2H-MoS2 via a diamond anvil cell (DAC) and density functional theory (DFT) calculations. The direct optical band gap of the monolayer 2H-MoS2 increases by 11.7% from 1.85 to 2.08 eV, which is the highest reported for a 2D transition metal dichalcogenide (TMD) material. DFT calculations reveal a subsequent decrease in the band gap with eventual metallization of the monolayer 2H-MoS2, an overall complex structure-property relation due to the rich band structure of MoS2. Remarkably, the metastable 1T′-MoS2 metallic state remains invariant with pressure, with the J2, A1g, and E2g modes becoming dominant at high pressures. This substantial reversible tunability of the electronic and vibrational properties of the MoS2 family can be extended to other 2D TMDs. These results present an important advance toward controlling the band structure and optoelectronic properties of monolayer MoS2 via pressure, which has vital implications for enhanced device applications.
SponsorsResearch at The University of Texas at Austin was supported in by a Young Investigator Award (D.A.) from the Defense Threat Reduction Agency (DTRA), the Army Research Office (ARO), and the Southwest Academy of Nanoelectronics (SWAN) center sponsored by the Semiconductor Research Corporation (SRC). Research at Indian Institute of Science was supported by National Program on Micro and Smart Systems (NpMASS) PARC No. 1:22 and DST Nanomission. We would like to thank Megan Matheney for providing critical feedback. J.F.L. acknowledges supports from Energy Frontier Research in Extreme Environments (EFree), Center for High Pressure Science and Advanced Technology (HPSTAR), and the U.S. National Science Foundation Geophysics Program. L.J.L. acknowledges support from Academia Sinica Taiwan and KAUST, Saudi Arabia.
PublisherAmerican Chemical Society (ACS)