Revealing the nature of low temperature photoluminescence peaks by laser treatment in van der Waals epitaxially grown WS2 monolayers

Henini, M. (2018) Revealing the nature of low temperature photoluminescence peaks by laser treatment in van der Waals epitaxially grown WS2 monolayers. Nanoscale . ISSN 2040-3372

[img] PDF - Repository staff only until 19 February 2019. - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (9MB)

Abstract

Monolayers of transition metal dichalcogenides (TMD) are promising materials for optoelectronics devices. However, one of the challenges is to fabricate large-scale growth of high quality TMD monolayers with the desired properties in order to expand their use in potential applications. Here, we demonstrate large-scale tungsten disulfide (WS2) monolayers grown by van der Waals Epitaxy (VdWE). We show that, in addition to the large structural uniformity and homogeneity of these samples, their optical properties are very sensitive to laser irradiation. We observe a time instability in the photoluminescence (PL) emission at low temperatures in the scale of seconds to minutes. Interestingly, this change of the PL spectra with time, which is due to laser induced carrier doping, is employed to successfully distinguish the emission of two negatively charged bright excitons. Furthermore, we also detect blinking sharp bound exciton emissions which are usually attractive for single photon sources. Our findings contribute to a deeper understanding of this complex carrier dynamics induced by laser irradiation which is very important for future optoelectronic devices based on large scale TMD monolayers.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1039/C8NR00719E
Depositing User: Henini, Mohamed
Date Deposited: 28 Feb 2018 13:49
Last Modified: 26 Jun 2018 12:43
URI: http://eprints.nottingham.ac.uk/id/eprint/49989

Actions (Archive Staff Only)

Edit View Edit View