Excitation dependent and time resolved photoluminescence of β-Ga2O3, β-(Ga0.955Al0.045)2O3 and β-(Ga0.91In0.09)2O3 epitaxial layers grown by pulsed laser deposition

We have performed steady state and time-resolved photoluminescence measurements on β-Ga2O3 and β-(Ga0.955Al0.045)2O3 and β-(Ga0.91In0.09)2O3 mixed crystals grown by pulsed laser deposition. The steady state luminescence spectra of all the samples are characterized by transitions in the form of peaks and shoulders. In both Ga2O3 and the alloy oxides there are two transitions in the wavelength ranges of 330–381 nm (ultraviolet) and 486–492 nm (blue). Additionally, in Ga2O3, emissions at 596 nm (yellow) and 734 nm (near infrared) are also observed. Only the yellow transition is observed in (Ga0.955Al0.045)2O3 at 582 nm and neither are observed in (Ga0.91In0.09)2O3. Steady state and time-resolved photoluminescence measurements were also made as a function of excitation intensity. The trend of the variation of integrated and peak intensity, peak position and recombination lifetimes of the transitions with excitation are examined and discussed in the context of the underlying recombination mechanisms.