Ultrafast hot electron-hole plasma photoluminescence in two-dimensional semiconductors
Journal article, 2023

The transition metal dichalcogenide family of semiconducting two-dimensional materials has recently shown a prominent potential to be an ideal platform to study the exciton Mott transition into electron-hole plasma and liquid phases due to their strong Coulomb interactions. Here, we show that pulsed laser excitation at high pump fluences can induce this exciton Mott transition to an electron-hole plasma in mono and few-layer transition metal dichalcogenides at room temperature. The formation of an electron-hole plasma leads to a broadband light emission spanning from the near infrared to the visible region. In agreement with our theoretical calculations, the photoluminescence emission at high energies displays an exponential decay that directly reflects the electronic temperature - a characteristic fingerprint of unbound electron-hole pair recombination. Furthermore, two-pulse excitation correlation measurements were performed to study the dynamics of electronic cooling, which shows two decay time components, one of less than 100 fs and a slower component of few ps associated with the electron-phonon and phonon-lattice bath thermalizations, respectively. Our work may shed light on further studies of the exciton Mott transition into other two-dimensional materials and their heterostructures and its applications in nanolasers and other optoelectronic devices.

Author

Frederico B. Sousa

Universidade Federal de Minas Gerais

Raul Perea Causin

Chalmers, Physics, Condensed Matter and Materials Theory

Sean Hartmann

Ludwig Maximilian University of Munich (LMU)

Lucas Lafetá

Ludwig Maximilian University of Munich (LMU)

Universidade Federal de Minas Gerais

Bárbara Rosa

Technische Universität Berlin

Samuel Brem

Philipps University Marburg

Chirag Palekar

Technische Universität Berlin

Stephan Reitzenstein

Technische Universität Berlin

A. Hartschuh

Ludwig Maximilian University of Munich (LMU)

Ermin Malic

Chalmers, Physics, Condensed Matter and Materials Theory

Philipps University Marburg

Leandro M. Malard

Universidade Federal de Minas Gerais

Nanoscale

2040-3364 (ISSN) 2040-3372 (eISSN)

Vol. 15 15 7154-7163

Graphene Core Project 3 (Graphene Flagship)

European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics

DOI

10.1039/d2nr06732c

More information

Latest update

3/7/2024 9