Intensity distribution around XRD reflections [(a) and (b)] (0002) reflections and [(c) and (d)] (−1−124) reflections for heterostructures grown on [(a) and (c)] thin substrates and [(b) and (d)] thick substrates.
(a) Raman spectra for different depth scans [points 1–5 in (b)] of an structure grown on a thick sapphire substrate (3 mm) (curves 1–4). Curve 5—Raman spectrum measured from the back side of this structure: and . (b) Measurement configuration using the axial focal spot of the laser beam from the front (points 1–4) and back side (point 5) of the investigated structure.
(a) Frequencies and the FWHM of the (GaN) phonon mode vs the excitation depth for the structure (Fig. 2), plotted as a function of the ratio of intensities . (b) Raman spectra for the phonon mode of the sapphire substrate under excitation from the nitride layers side (curve 1) and back side (curve 2) of the investigated structure.
[(a) and (b)] Raman spectra of the structure grown on a thin sapphire substrate measured at excitation from the nitride layers side (curve 1) and back side (curve 2) at depths shown schematically by drawn points 1 and 2 in (c), respectively: and .
Structural parameters obtained from the XRD data.
Macrodeformation and curvature radius of the GaN layers.
Article metrics loading...
Full text loading...