Manipulation of exciton and trion quasiparticles in monolayer WS2 via charge transfer

• Published in: Applied physics letters Vol. 115; no. 17
• Main Authors: Gaur, Anand P. S., Rivera, Adriana M., Dash, Saroj P., Dey, Sandwip, Katiyar, Ram S., Sahoo, Satyaprakash
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.10.2019
• Subjects: Applied physics; Charge transfer; Doping; Dynamic stability; Electrical properties; Emission spectra; Excitons; Monolayers; Optical properties; Optoelectronics; Organic chemistry; Photoluminescence; Temperature dependence; Transition metal compounds; Trions
• ISSN: 0003-6951; 1077-3118; 1077-3118
• DOI: 10.1063/1.5113775

Charge doping in transition metal dichalcogenide is currently a subject of high importance for future electronic and optoelectronic applications. Here, we demonstrate chemical doping in the CVD-grown monolayer (1L) of WS2 by a few commonly used laboratory solvents by investigating the room temperature photoluminescence (PL). The appearance of distinct trionic emission in the PL spectra and quenched PL intensities suggests n-type doping in WS2. The temperature-dependent PL spectra of the doped 1L-WS2 reveal a significant enhancement of trions emission intensity over the excitonic emission at low temperature, indicating the stability of trion at low temperature. The temperature-dependent exciton-trion population dynamic has been modeled using the law of mass action of trion formation. These results shed light on the solution-based chemical doping in 1L-WS2 and its profound effect on the photoluminescence which is essential for the control of optical and electrical properties for optoelectronic applications.