Structural and optical qualities of half-a-μm-thick m-plane Al1-xInxN epilayers grown by metalorganic vapor phase epitaxy were remarkably improved via coherent growth on a low defect density m-plane freestanding GaN substrate prepared by hydride vapor phase epitaxy. All the epilayers unexceptionally suffer from uniaxial or biaxial anisotropic in-plane stress. However, full-width at half-maximum values of the x-ray ω-rocking curves were nearly unchanged as the underlayer values being 80 ∼ 150 arc sec for (10 1 ¯ 0) and (10 1 ¯ 2) diffractions with both 〈 0001 〉 and 〈 11 2 ¯ 0 〉 azimuths, as long as pseudomorphic structure was maintained. Such Al1-xInxN epilayers commonly exhibited a broad but predominant luminescence peak in ultraviolet (x ≤ 0.14) to green (x = 0.30) wavelengths. Its equivalent value of the internal quantum efficiency at room temperature was as high as 67% for x = 0.14 and 44% for x = 0.30. Because its high-energy cutoff commonly converged with the bandgap energy, the emission peak is assigned to originate from the extended near-band-edge states with strong carrier localization.
ASJC Scopus subject areas
- Physics and Astronomy(all)