Optically Discriminating Carrier-Induced Quasiparticle Band Gap and Exciton Energy Renormalization in Monolayer MoS_{2}

Kaiyuan Yao; Aiming Yan; Salman Kahn; Aslihan Suslu; Yufeng Liang; Edward S Barnard; Sefaattin Tongay; Alex Zettl; Nicholas J Borys; P James Schuck

doi:10.1103/PhysRevLett.119.087401

Optically Discriminating Carrier-Induced Quasiparticle Band Gap and Exciton Energy Renormalization in Monolayer MoS_{2}

Phys Rev Lett. 2017 Aug 25;119(8):087401. doi: 10.1103/PhysRevLett.119.087401. Epub 2017 Aug 25.

Authors

Kaiyuan Yao^{1

2}, Aiming Yan^{3

4}, Salman Kahn³, Aslihan Suslu⁵, Yufeng Liang¹, Edward S Barnard¹, Sefaattin Tongay⁵, Alex Zettl^{3

4

6}, Nicholas J Borys^{1

7}, P James Schuck^{1

8}

Affiliations

¹ Molecular Foundry Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
² Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA.
³ Department of Physics, University of California, Berkeley, California 94720, USA.
⁴ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁵ Department of Materials Science and Engineering, Arizona State University, Tempe, Arizona 85287, USA.
⁶ Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁷ Department of Physics, Montana State University, Bozeman, Montana 59717, USA.
⁸ Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA.

PMID: 28952768
DOI: 10.1103/PhysRevLett.119.087401

Abstract

Optoelectronic excitations in monolayer MoS_{2} manifest from a hierarchy of electrically tunable, Coulombic free-carrier and excitonic many-body phenomena. Investigating the fundamental interactions underpinning these phenomena-critical to both many-body physics exploration and device applications-presents challenges, however, due to a complex balance of competing optoelectronic effects and interdependent properties. Here, optical detection of bound- and free-carrier photoexcitations is used to directly quantify carrier-induced changes of the quasiparticle band gap and exciton binding energies. The results explicitly disentangle the competing effects and highlight longstanding theoretical predictions of large carrier-induced band gap and exciton renormalization in two-dimensional semiconductors.