Articolo in rivista, 2016, ENG, 10.1088/0953-8984/28/22/224005

Theoretical and experimental investigation of optical absorption anisotropy in beta-Ga2O3

Ricci, F.; Boschi, F.; Baraldi, A.; Filippetti, A.; Higashiwaki, M.; Kuramata, A.; Fiorentini, V.; Fornari, R.

Univ Cagliari; Univ Parma; UOS Cagliari; Natl Inst Informat & Commun Technol; Tamura Corp

The question of optical bandgap anisotropy in the monoclinic semiconductor beta-Ga2O3 was revisited by combining accurate optical absorption measurements with theoretical analysis, performed using different advanced computation methods. As expected, the bandgap edge of bulk beta-Ga2O3 was found to be a function of light polarization and crystal orientation, with the lowest onset occurring at polarization in the ac crystal plane around 4.5-4.6 eV; polarization along b unambiguously shifts the onset up by 0.2 eV. The theoretical analysis clearly indicates that the shift in the b onset is due to a suppression of the transition matrix elements of the three top valence bands at Gamma point.

Journal of physics. Condensed matter (Print) 28 (22)

Keywords

optical absorption, ab initio band theory, optical polarization

CNR authors

Fiorentini Vincenzo, Filippetti Alessio

CNR institutes

IOM – Istituto officina dei materiali