Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 17: Poster Ib
HL 17.16: Poster
Freitag, 4. März 2005, 16:30–19:00, Poster TU F
Optical phonons and infrared dielectric functions of hexagonal and cubic MgZnO thin films — •C. Bundesmann, M. Schubert, A. Rahm, D. Spemann, H. Hochmuth, E. M. Kaidashev, M. Lorenz und M. Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, D-04103 Leipzig, Germany
Infrared spectroscopic ellipsometry (IRSE) and Raman scattering is applied to study the phonon modes and infrared dielectric functions of MgxZn1−xO thin films, which are grown by pulsed laser deposition on c-plane and r-plane sapphire. X-ray diffraction reveals a hexagonal structure for the MgxZn1−xO thin films with x≤0.53, whereas a cubic structure is found for the MgxZn1−xO thin films with x≥0.67. The cubic MgxZn1−xO thin films show a one mode behavior, where the TO and LO phonon modes shift linearly with x.[3] The hexagonal c-plane oriented MgxZn1−xO thin films on c-plane sapphire show two modes each for polarizations E⊥c and E||c.[1,2] The phonon mode behavior with x can be described by the modified random element isodisplacement model.[4] Furthermore, generalized IRSE is applied to a-plane MgZnO thin films on r-plane sapphire, which allows to access the full set of infrared dielectric tensor parameters.[5] For the a-plane MgZnO thin films three phonon modes each for polarizations E⊥c and E||c are detected.
[1] C. Bundesmann et. al, Appl. Phys. Lett. 81, 2376-2378 (2002).
[2] R. Schmidt et. al, Proc. 26th ICPS, Edinburgh, UK (2002).
[3] C. Bundesmann et. al, Appl. Phys. Lett. 85, 905-907 (2004).
[4] J. Chen and W. Z. Shen, Appl. Phys. Lett. 83, 2154 (2003).
[5] C. Bundesmann et. al, Thin Solid Films 455-456C, 161-166 (2004).