Vibrational spectroscopy of O-H centers in Ga₂O₃

Hydrogen has a strong influence on the electrical properties of transparent conducting oxides where it can give rise to shallow donors and can passivate deep compensating defects. The ultra-wide bandgap semiconducting oxide Ga₂O₃ is no exception [1,2]. Vibrational spectroscopy shows that the introduction of H into Ga₂O₃ produces several O-H centers with strongly polarized vibrational lines and different thermal stabilities. Some of these defects appear to be shallow donors and others to be V_Ga-nH centers. Measurements made for samples that contain both H and D provide clues about the number of H atoms each of these defects contains. Our results suggest different O-H centers that contain a single H atom , two equivalent H atoms, and three or more H atoms. The polarization properties and mode coupling effects for these O-H centers provide structure-sensitive information for complementary theory that suggests specific defect structures [3].
[1] J. Varley et al., Appl. Phys. Lett. 97, 142106 (2010).
[2] P. Weiser et al., Appl. Phys. Lett. 112, 232104 (2018).
[3] W.B. Fowler et al., Multiple O-H centers in β-Ga₂O₃, this session.