Electron Energy Loss Spectroscopy of III-Nitride Semiconductors
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
This Licentiate Thesis covers experimental and theoretical investigations of the bulk plasmon response to different compositions and strain states of group III-nitride materials. Investigated materials were grown using magnetron sputtering epitaxy and metal organic chemical vapour deposition and studied by Rutherford backscattering spectrometry, X-ray diffraction, electron microscopy and electron energy loss spectroscopy (EELS).
It is shown that low-loss EELS is a powerful method for a fast compositional determination in AlxIn1-xN system. The bulk plasmon energy of the investigated material system follows a linear relation with respect to lattice parameter and composition in unstrained layers.
Furthermore, the effect of strain on the bulk plasmon peak position has been investigated by using low-loss EELS in group III-nitrides. We experimentally determine the AlN bulk plasmon peak shift of 0.156 eV per 1% volume change. The AlN peak shift was corroborated by full potential calculations (Wein2k), which reveal that the bulk plasmon peak position of III-nitrides varies near linearly with unit cell volume variations.
Finally, self-assembled ternary Al1-xInxN nanorod arrays with variable In concentration have been realized onto c-plane sapphire substrates by ultra-high-vacuum magnetron sputtering epitaxy with Ti0.21Zr0.79N or VN seed layer assistance. The nanorods exhibit hexagonal cross-sections with preferential growth along the Al1-xInxN c-axis. A coaxial rod structure with higher In concentration in the core was observed by scanning transmission electron microscopy in combination with low-loss EELS.
Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press , 2011. , 47 p.
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1487
IdentifiersURN: urn:nbn:se:liu:diva-67985Local ID: LIU-TEK-LIC-2011:26ISBN: 978-91-7393-161-8OAI: oai:DiVA.org:liu-67985DiVA: diva2:414798
2011-06-01, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Coronel, Ernesto, Dr.
Persson, Per, Dr.Hultman, Lars, ProfessorBirch, Jens, Professor
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