High-quality III-nitride films on conductive, transparent (201)-oriented ?-Ga2O3 using a GaN buffer layer.

ABSTRACT: We demonstrate the high structural and optical properties of InxGa1-xN epilayers (0???x???23) grown on conductive and transparent (01)-oriented ?-Ga2O3 substrates using a low-temperature GaN buffer layer rather than AlN buffer layer, which enhances the quality and stability of the crystals compared to those grown on (100)-oriented ?-Ga2O3. Raman maps show that the 2? wafer is relaxed and uniform. Transmission electron microscopy (TEM) reveals that the dislocation density reduces considerably (~4.8?×?10(7)?cm(-2)) at the grain centers. High-resolution TEM analysis demonstrates that most dislocations emerge at an angle with respect to the c-axis, whereas dislocations of the opposite phase form a loop and annihilate each other. The dislocation behavior is due to irregular (01) ?-Ga2O3 surface at the interface and distorted buffer layer, followed by relaxed GaN epilayer. Photoluminescence results confirm high optical quality and time-resolved spectroscopy shows that the recombination is governed by bound excitons. We find that a low root-mean-square average (?1.5?nm) of InxGa1-xN epilayers can be achieved with high optical quality of InxGa1-xN epilayers. We reveal that (01)-oriented ?-Ga2O3 substrate has a strong potential for use in large-scale high-quality vertical light emitting device design.

SUBMITTER: Muhammed MM 

PROVIDER: S-EPMC4944183 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature