Kinetic Monte‐Carlo Simulation of Exciton Hopping: Urbach Tails in Gas‐Molecule Decorated MoSe2. Issue 11 (24th September 2021)

• Record Type: Journal Article
• Authors: Wagner, Christian; Schwuchow, Maik; Venanzi, Tommaso; Schneider, Harald; Winnerl, Stephan; Thränhardt, Angela
• Is Part Of: Physica status solidi. Volume 258:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-24
• Subjects: 2D materials -- dichalcogenides -- disorder -- low temperature -- molybdenum selenide -- optical properties -- Urbach tail; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202100186
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : Disorder parameters of gas‐molecule decorated monolayer MoSe 2 are quantitatively investigated. This material system is interesting because disorder may be introduced and removed at will by regulating the number of adsorbed gas molecules through laser annealing. These molecules electrostatically trap excitons leading to localized defect states, which are exponentially distributed in energy. Herein, experiments are described by kinetic Monte‐Carlo simulations, in summary enabling richer studies than within crystalline materials with a fixed degree of disorder. It is found that the surface coverage of the MoSe2 may reach up to one molecule per 2 nm 2 and that the density of adsorbed molecules depends on the laser power by a power law. Abstract : Photoluminescence spectra of MoSe2 decorated with gas molecules generating electrostatic disorder are analyzed and simulated. Kinetic Monte‐Carlo simulations reproduce optical spectra by showing that the disorder energy scale (Urbach energy) of the excitons is temperature‐dependent. A laser annealing study reveals desorption kinetics of the gas molecules and enables to estimate the surface density of the molecules.