Modeling and interpretation of UV and blue luminescence intensity in beta-Ga2O3 by silicon and nitrogen doping

Temperature-dependent cathodoluminescence spectra of ((2) over bar1) Si-doped beta-Ga2O3 single crystals and (010) N-doped epitaxial films were comprehensively shown to investigate their electronic structure and defect states. The decrease in the self-trapped exciton (STE) emission at low temperatures in heavily Si-doped crystals implied the Debye-Hickel screening of STEs with the critical charge density larger than 2 x 10(18) cm(-3). The analysis based on the rate equation model suggested a significant influence of the donor-acceptor-pair recombination involving a Si-Ga, donor on the UV luminescence band in the Si-doped crystals. The blue luminescence band was suppressed for the heavily N-doped epitaxial films with a N concentration of 1 x 10(18 )cm(-3), implying the decrease in the oxygen vacancy (V-O) concentration by N doping. The increase in the N-O acceptor concentration as well as the decrease in the V-O concentration were found to contribute to the compensation of residual Si donors resulting in high resistivity of N-doped epitaxial films. Published by AIP Publishing.