Luminescence properties related anti-phase domain of alpha-Ga2O3

This work investigates the relationship between atomic arrangement and luminescence properties in a high-quality alpha-Ga2O3 thin film grown on an Al2O3 single-crystal membrane. The strain induced by merging domain boundaries shows more significant variability in annular darkfield images even though there is no additional gallium concentration confirmed. The bandgap energy of alpha-Ga2O3 is estimated to be 5.56 eV from the CL measurement in a transmission electron microscope. A peak at 320 nm was observed within the domain, while the domain boundary showed spectrum peaks with 380–480 nm. The anti-phase domain (APD) is formed by the instabilities of Al–O bonding templates provided by the Al2O3 substrate. The APD boundary gives a characteristic wavelength of 350 nm, which is the result of the merging boundary of in-phase and anti-phase domains.