Oxidation of ultrathin GaSe

Abstract

Oxidation of exfoliated gallium selenide (GaSe) is investigated through Raman, photoluminescence, Auger, and X-ray photoelectron spectroscopies. Photoluminescence and Raman intensity reductions associated with spectral features of GaSe are shown to coincide with the emergence of signatures emanating from the by-products of the oxidation reaction, namely, Ga2Se3 and amorphous Se. Photoinduced oxidation is initiated over a portion of a flake highlighting the potential for laser based patterning of two-dimensional heterostructures via selective oxidation.

Oxidation dynamics of ultrathin GaSe probed through Raman spectroscopy

“…The first at 130 cm −1 likely corresponds to SeO 2 or SeO 3 Raman modes 36,37 , but a quantitative analysis of this feature has proven difficult; it will not be further discussed. The other feature at 257 cm −1 matches the characteristics of a mode associated to selenium 26,38 and its width (∼20 cm −1 ) suggests an amorphous phase (a-Se) 39,40 . The narrower peak (∼5 cm −1 ) at 241 cm −1 appears last and is associated 41 to a selenium crystalline phase (c-Se).…”

“…Nonetheless, bulk GaSe is also known to naturally form a native oxide 22 and thermally-and photo-induced oxidation has been reported [23][24][25] . Recently, exposure to intense laser light was found to degrade optical properties and lead to chemical transformations [26][27][28] . Given the interest for few-layer GaSe for electronic and optoelectronic applications, it appears critical to examine the oxidation dynamics of ultrathin GaSe and determine the conditions in which this oxidation can be suppressed or at least minimized.…”

Crystal quality of two-dimensional gallium telluride and gallium selenide using Raman fingerprint

“…This result shows a good agreement with the recent report. 27 Oxidisation also produces Ga 2 Se 3 and Ga 2 O 3 which can be detected by Raman at 150 cm -1 and at 233 cm -1 , respectively. 27 These two peaks at 150 cm -1 and at 233 cm -1 are not clearly visible in our Raman measurements.…”

“…27 Oxidisation also produces Ga 2 Se 3 and Ga 2 O 3 which can be detected by Raman at 150 cm -1 and at 233 cm -1 , respectively. 27 These two peaks at 150 cm -1 and at 233 cm -1 are not clearly visible in our Raman measurements. The a-Se peak becomes prominent due to oxidisation whereas intensities of other GaSe peaks reduce.…”

“…Recent reports have shown atmospheric induced degradation of optical properties of ultrathin GaSe. 27 Thermally activated Ga vacancy defects in multilayer GaTe has been reported in field effect transistor (FET) and phototransistor application. 28 The thicknesses dependent PL of GaTe and GaSe films has also been reported, where in both materials, PL shows a dramatic decrease of intensity at a reduced film thickness due to non-radiative carrier escape via surface states.…”