Weak metastability of Al x Ga1−x N (x = 13/24, 15/24, 17/24) shown by analyzing AlGaN grown on AlN with dense macrosteps

Abstract Energy-dispersive X-ray signals calibrated by Rutherford backscattering indicated the generation of Al 13/24 Ga 11/24 N in Ga-rich stripes in a nonflat Al 0.58 Ga 0.42 N layer. Also, the CL peak wavelengths of ∼259 and 272 nm also showed the generation of Al 15/24 Ga 9/24 N and Al 13/24 Ga 11/24 N in Al-rich zones and Ga-rich stripes, respectively. The wavelength of a strong CL peak at ∼246 nm, which was observed from the Al 0.7 Ga 0.3 N layer in our previous study, is also considered to correspond to the near-band-emission wavelengths of Al 17/24 Ga 7/24 N. In particular, the stronger reproducibility of metastable Al 15/24 Ga 9/24 N generation was confirmed, in agreement with the computed predictions by other research groups.