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

We have established Raman fingerprint of GaTe and GaSe to investigate their crystal quality. As unencapsulated, they both oxidise in ambient conditions which can be detected in their Raman analysis. X-ray photoelectron spectroscopy (XPS) analysis shows a good agreement with Raman analysis. 50-nm-thick Al2O3 encapsulation layer deposited by atomic layer deposition (ALD) inhibits degradation in ambient conditions. (C) 2017 Author(s).