High-quality III-nitride films on conductive, transparent (2̅01)-oriented β-Ga(2)O(3) using a GaN buffer layer

We demonstrate the high structural and optical properties of In(x)Ga(1−x)N epilayers (0 ≤ x ≤ 23) grown on conductive and transparent ([Image: see text]01)-oriented β-Ga(2)O(3) 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 β-Ga(2)O(3). 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 ([Image: see text]01) β-Ga(2)O(3) 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 In(x)Ga(1−x)N epilayers can be achieved with high optical quality of In(x)Ga(1−x)N epilayers. We reveal that ([Image: see text]01)-oriented β-Ga(2)O(3) substrate has a strong potential for use in large-scale high-quality vertical light emitting device design.