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Infrared dielectric functions and optical phonons of wurtzite YxAl1-xN (0 <= x <= 0.22)

 
: Ben Sedrine, N.; Zukauskaite, A.; Birch, J.; Jensen, J.; Hultman, L.; Schöche, S.; Schubert, M.; Darakchieva, V.

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Journal of Physics. D. Applied Physics 48 (2015), Nr.41, Art. 415102
ISSN: 0022-3727
ISSN: 1361-6463
Englisch
Zeitschriftenaufsatz
Fraunhofer IAF ()

Abstract
YAlN is a new member of the group-III nitride family with potential for applications in next generation piezoelectric and light emitting devices. We report the infrared dielectric functions and optical phonons of wurtzite (0001) YxAl1-xN epitaxial films with 0 <= x <= 0.22. The films are grown by magnetron sputtering epitaxy on c-plane Al2O3 and their phonon properties are investigated using infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The infrared-active E-1(TO) and LO, and the Raman active E-2 phonons are found to exhibit one-mode behavior, which is discussed in the framework of the MREI model. The compositional dependencies of the E-1(TO), E-2 and LO phonon frequencies, the high-frequency limit of the dielectric constant, epsilon(infinity), the static dielectric constant, epsilon(0), and the Born effective charge Z(B) are established and discussed.

: http://publica.fraunhofer.de/dokumente/N-369419.html