Browsing by Subject "Mosaic structure"
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Item Open Access Mosaic structure characterization of the AlInN layer grown on sapphire substrate(Hindawi Publishing Corporation, 2014) Arslan, E.; Demirel P.; Çakmak H.; Öztürk, M.K.; Özbay, EkmelThe 150 nm thick, (0001) orientated wurtzite-phase Al1-x InxN epitaxial layers were grown by metal organic chemical vapor deposition on GaN (2.3 μm) template/(0001) sapphire substrate. The indium (x) concentration of the Al1-x InxN epitaxial layers was changed as 0.04, 0.18, 0.20, 0.47, and 0.48. The Indium content (x), lattice parameters, and strain values in the AlInN layers were calculated from the reciprocal lattice mapping around symmetric (0002) and asymmetric (10-15) reflection of the AlInN and GaN layers. The mosaic structure characteristics of the AlInN layers, such as lateral and vertical coherence lengths, tilt and twist angle, heterogeneous strain, and dislocation densities (edge and screw type dislocations) of the AlInN epilayers, were investigated by using high-resolution X-ray diffraction measurements and with a combination of Williamson-Hall plot and the fitting of twist angles. Copyright © 2014 Engin Arslan et al.Item Open Access Structural analysis of an InGaN/GaN based light emitting diode by X-ray diffraction(Springer, 2009-04-18) Öztürk, M. K.; Hongbo, Y.; SarIkavak, B.; Korçak, S.; Özçelik, S.; Özbay, EkmelThe important structural characteristics of hexagonal GaN in an InGaN/GaN multi quantum well, which was aimed to make a light emitted diode and was grown by metalorganic chemical vapor deposition on c-plain sapphire, are determined by using nondestructive high-resolution X-ray diffraction in detail. The distorted GaN layers were described as mosaic crystals characterized by vertical and lateral coherence lengths, a mean tilt, twist, screw and edge type threading dislocation densities. The rocking curves of symmetric (00.l) reflections were used to determine the tilt angle, while the twist angle was an extrapolated grown ω-scan for an asymmetric (hk.l) Bragg reflection with an h or k nonzero. Moreover, it is an important result that the mosaic structure was analyzed from a different (10.l) crystal direction that was the angular inclined plane to the z-axis. The mosaic structure parameters were obtained in an approximately defined ratio depending on the inclination or polar angle of the sample.