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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.40: Poster

Mittwoch, 27. Februar 2008, 16:30–19:00, Poster D

Near infrared absorption in nonpolar cubic AlN/GaN superlattices — •Jörg Schörmann¹, Elena Tschumak¹, Donat J. As¹, Klaus Lischka¹, Eric A. DeCuir², and Omar Manasreh² — ¹Department of Physics, University of Paderborn, Warburger Str. 100, 33095 Paderborn — ²Department of Electrical Engineering, University of Arkansas, 3217 Bell Engineering Center, Fayetteville, Arkansas 72701

Nonpolar cubic GaN/AlN superlattices were grown at 720^∘C by plasma-assisted molecular beam epitaxy on free standing 3C-SiC substrates. 20 periods of AlN/GaN quantum wells were deposited on a 100 nm thick GaN buffer layer. The thickness of the AlN barrier is 1.35 nm for all samples, while the thickness of the GaN well varies between 1.6 nm - 2.10 nm depending on the samples. The periodicity of the GaN/AlN active regions was confirmed by the presence of several peaks in the high resolution x-ray diffraction (HRXRD) spectra. The thickness of the total period was estimated by fitting the HRXRD data using a dynamic scattering theory. Room temperature optical absorption spectra of the intersubband transitions were obtained using a Bruker IFS-125HR spectrometer. Optical absorption was observed in the spectral range of 1.5 µm - 2.0 µm and confirmed theoretically using a square well self-consistent Poisson-Schrödinger model.