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Structural and spectroscopic properties of AlN layers grown by MOVPE
Auteur(s)
Thapa, S. B.
Kirchner, C.
Scholz, F.
Prinz, G. M.
Thonke, K.
Sauer, R.
Chuvilin, A.
Biskupek, J.
Kaiser, U.
Date de parution
2007
In
Journal of Crystal Growth, Elsevier, 2007/298//383-386
Résumé
The effects on surface morphology, crystal quality, and growth rate of undoped AlN layers grown on c-plane sapphire substrates due to the changes in growth parameters, such as V–III ratio, N<sub>2</sub>–H<sub>2</sub> ratio, and growth temperature in LP-MOVPE are studied here. The optimized growth process resulted in an almost flat surface morphology with a significantly reduced number of hexagonal pits (3 x 10<sup>7</sup> cm<sup>-2</sup>) and good crystalline quality having a rms value of roughness of 0.4 nm measured by atomic force microscopy and a high resolution X-ray diffraction (HRXRD) FWHM value for (0 0 0 2) reflection of 200 arcsecs. The threading dislocation density of the AlN layer is estimated approx. 10<sup>9</sup> cm<sup>-2</sup> from cross-sectional transmission electron microscopy (TEM) measurements. Additionally, these optimized samples show a strong donor-bound exciton luminescence signal with a FWHM of 20 meV. Furthermore, small period AlN/GaN superlattice structures with excellent uniformity were grown, as proven by our HRXRD and TEM studies.
Identifiants
Type de publication
journal article
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