Electron-irradiation induced unconventional phase transition of β-Ga2O3 epitaxial single-crystal thin film observed by in-situ TEM
Qing Zhu, Jiatong Fan, Yuxiang Wei, Zhan Wang, Jiejie Zhu, Jing Sun, Zhenni Wang, Xichen Wang, Ling Yang, Shaojie Song, Yimin Lei, Xiaohua Ma
Abstract
In this work, the phase transition process of β-Ga2O3 thin films under heating and (or) electron irradiation condition was investigated by in-situ transmission electron microscopy. It is found that only under the high temperature, β-Ga2O3 did not undergo phase transition even when the temperature was up to 1000 °C. When under electron irradiation condition, the unconventional phase transition from β-Ga2O3 to δ-Ga2O3 occurred with a slow rate. When electron irradiation was coupled with a thermal field, the initial temperature of phase transition decreased, and the speed of phase transition also greatly accelerated. The new phase maintains crystallography relationship with the β-Ga2O3 parent phase as following: [010]β//[011¯]δ, (200)β//(2¯11)δ, and (402¯)β//(411)δ. The results reveal that electron irradiation can trigger the phase transition process from β-Ga2O3 to δ-Ga2O3, and the high temperature obviously accelerates the rate of phase transition process.