In:
Physical Chemistry Chemical Physics, Royal Society of Chemistry (RSC), Vol. 23, No. 43 ( 2021), p. 24579-24588
Abstract:
The low photoluminescence (PL) quantum yields of transition metal dichalcogenide monolayers have been a limiting factor for their optoelectronic applications. Various and even inconsistent mechanisms have been proposed to modulate their PL efficiencies. Herein, we use PL/Raman microspectroscopy and the corresponding in situ mapping, atomic force microscopy, and field-effect transistor (FET) characterization to investigate the changes in the structural and optical properties of monolayer MoS 2 . Relatively low power density ( 〈 4.08 × 10 5 W cm −2 ) of laser irradiation in ambient air can cause a slight PL suppression effect on monolayer MoS 2 , whereas relatively high power density (∼1.02 × 10 6 W cm −2 ) of laser irradiation brings significant PL enhancement. Experiments under different atmospheres reveal that the laser-irradiation-induced enhancement only occurs in the atmosphere containing O 2 and is more remarkable in pure O 2 . In addition, physically adsorbed water can also induce PL enhancement of monolayer MoS 2 . FET devices suggest that the adsorbed water produces a p-doping effect on MoS 2 , and the laser irradiation in ambient air generates an n-doping effect, and both types of doping can enhance the PL intensity. The island-shaped defects caused by laser irradiation can be stabilized by oxygen atoms and act as trapping centers for excited trions or electrons, thus reducing the non-radiative recombination ratio and enhancing the PL intensity. The physically adsorbed water works in a similar way. A low power density of laser irradiation can sweep away the originally adsorbed H 2 O on the surface, thus reducing the PL.
Type of Medium:
Online Resource
ISSN:
1463-9076
,
1463-9084
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2021
detail.hit.zdb_id:
1476283-3
detail.hit.zdb_id:
1476244-4
detail.hit.zdb_id:
1460656-2
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