Excitation and photoluminescence of pure and Si-doped β-Ga2O3 single crystals

Excitation and photoluminescence spectra of high purity and Si-doped beta-Ga2O3 single crystals are investigated. Emission peaks in the UV and blue wavelength regions are observed. These are excited at two bands, which can be differentiated by polarized light. The features of the spectra are independent of excitation and emission wavelengths in the case of an undoped sample. On the contrary, after Si doping, the blue emission becomes strongly dependent. A model to interpret the characteristics of blue luminescence is proposed. (C) 2008 American Institute of Physics.