| Autor: |
Filintoglou, K., Katsikini, M., Arvanitidis, J., Christofilos, D., Lotsari, A., Dimitrakopulos, G. P., Vouroutzis, N., Ajagunna, A. O., Georgakilas, A., Zoumakis, N., Kourouklis, G. A., Ves, S. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2015, Vol. 117 Issue 7, p075302-1-075302-11, 11p, 2 Diagrams, 3 Charts, 5 Graphs |
| Abstrakt: |
Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane (11120) and semipolar s-plane (10111) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A1(TO), E1(TO), and Eh 2 on the angle w that corresponds to rotation around the growth axis, is very well reproduced by using expressions taking into account the corresponding Raman tensors and the experimental geometry, providing thus a reliable technique towards assessing the sample quality. The s- and a-plane InN epilayers grown on nitridated r-plane sapphire (Al2O3) exhibit good crystalline quality as deduced from the excellent fitting of the experimental angle-dependent peak intensities to the theoretical expressions as well as from the small width of the Raman peaks. On the contrary, in the case of the s-plane epilayer grown on non-nitridated r-plane sapphire, fitting of the angular dependence is much worse and can be modeled only by considering the presence of two structural modifications, rotated so as their c-axes are almost perpendicular to each other. Although the presence of the second variant is verified by transmission electron and atomic force microscopies, angular dependent Raman spectroscopy offers a nondestructive and quick way for its quantification. Rapid thermal annealing of this sample did not affect the angular dependence of the peak intensities. The shift of the E1(TO) and Eh 2 Raman peaks was used for the estimation of the strain state of the samples. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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