CUED Publications database

Ultra-low power threshold for laser induced changes in optical properties of 2D molybdenum dichalcogenides

Cadiz, F and Robert, C and Wang, G and Kong, W and Fan, X and Blei, M and Lagarde, D and Gay, M and Manca, M and Taniguchi, T and Watanabe, K and Amand, T and Marie, X and Renucci, P and Tongay, S and Urbaszek, B (2016) Ultra-low power threshold for laser induced changes in optical properties of 2D molybdenum dichalcogenides. 2D Materials, 3. 045008-045008. ISSN 2053-1583

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© 2016 IOP Publishing Ltd. The optical response of traditional semiconductors depends on the laser excitation power used in experiments. For two-dimensional (2D) semiconductors, laser excitation effects are anticipated to be vastly different due to complexity added by their ultimate thinness, high surface to volume ratio, and laser-membrane interaction effects. We show in this article that under laser excitation the optical properties of 2D materials undergo irreversible changes in vacuum. Most surprisingly these effects take place even at low steady state excitation, which is commonly thought to be non-intrusive. In low temperature photoluminescence (PL) we show for monolayer (ML) MoSe2samples grown by different techniques that laser treatment increases significantly the trion (i.e. charged exciton) contribution to the emission compared to the neutral exciton emission. Comparison between samples exfoliated onto different substrates shows that laser induced doping is more efficient for ML MoSe2on SiO2/Si compared to h-BN and gold. For ML MoS2we show that exposure to laser radiation with an average power in the μW μm-2range does not just increase the trion-to-exciton PL emission ratio, but may result in the irreversible disappearance of the neutral exciton PL emission and a shift of the main PL peak to lower energy.

Item Type: Article
Uncontrolled Keywords: MoS2 MoSe2 photoluminescence optical properties doping
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 20:04
Last Modified: 19 Jul 2018 06:45