Oxidation dynamics of ultrathin GaSe probed through Raman spectroscopy

Gallium selenide (GaSe) is a 2D material with a thickness-dependent gap, strong non-linear optical coefficients and uncommon interband optical selection rules, making it interesting for optoelectronic and spintronic applications. In this work, we monitor the oxidation dynamics of GaSe with thickness...

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Vydáno v:arXiv.org
Hlavní autoři: Bergeron, Alaric, Ibrahim, John, Leonelli, Richard, Francoeur, Sébastien
Médium: Paper
Jazyk:angličtina
Vydáno: Ithaca Cornell University Library, arXiv.org 12.06.2017
Témata:
Ambient temperature
Charge transfer
Current carriers
Gallium selenides
Humidity
Illumination
Optical measurement
Optoelectronics
Oxidation
Raman spectra
Raman spectroscopy
Selenium
Spectrum analysis
Thickness
Two dimensional materials
ISSN:2331-8422
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Popis
Shrnutí:Gallium selenide (GaSe) is a 2D material with a thickness-dependent gap, strong non-linear optical coefficients and uncommon interband optical selection rules, making it interesting for optoelectronic and spintronic applications. In this work, we monitor the oxidation dynamics of GaSe with thicknesses ranging from 10 to 200 nm using Raman spectroscopy. In ambient temperature and humidity conditions, the intensity of all Raman modes and the luminescence decrease rapidly with moderate exposure to above-gap illumination. Concurrently, several oxidation products appear in the Raman spectra: Ga\(_2\)Se\(_3\), Ga\(_2\)O\(_3\) and amorphous and crystalline selenium. We find that no safe measurement power exists for optical measurements on ultrathin GaSe in ambient conditions. We demonstrate that the simultaneous presence of oxygen, humidity, and above-gap illumination is required to activate this photo-oxidation process, which is attributed to the transfer of photo-generated charge carriers towards aqueous oxygen at the sample surface, generating highly reactive superoxide anions that rapidly degrade the sample and quench the optical response of the material.
Bibliografie:SourceType-Working Papers-1
ObjectType-Working Paper/Pre-Print-1
content type line 50
ISSN:2331-8422
DOI:10.48550/arxiv.1612.06907