Luminescence of α-Ga2O3 Semiconductors

Abstract

Wide bandgap semiconductor α-Ga2O3 films were prepared by low temperature atomic layer deposition (ALD) which were subsequently annealed at 400 ℃ under different atmospheres (oxygen, Forming gas (3% H2, 97% N2), air and argon). The photoluminescence of each sample under UV excitation of 355 nm by Nd:YAG laser was conducted to understand the emission spectrum. The results were analyzed using Origin software. The range of the analyzed spectrum graphs is between 391 nm and 650 nm. Blue-green emission bands were observed and five peaks were identified and centered around 415 nm (~2.9 eV), 437 nm (~2.83 eV), 461 nm (~2.68 eV), 483 nm (~2.56 eV) and 541 nm (~2.29 eV). The sample annealed in oxygen showed the most intense emissions of blue-green among other samples. These emissions resulted from the band to band transitions where donor state are formed by oxygen vacancy or interstitial Ga atom Gai .. and acceptor state gallium vacancy VGaor oxygen-gallium vacancy pair (VO-VGa)