O
Oliver Ambacher
Researcher at Fraunhofer Society
Publications - 862
Citations - 29006
Oliver Ambacher is an academic researcher from Fraunhofer Society. The author has contributed to research in topics: Amplifier & Monolithic microwave integrated circuit. The author has an hindex of 64, co-authored 848 publications receiving 26256 citations. Previous affiliations of Oliver Ambacher include Osram & Siemens.
Papers
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Evidence for nonlinear macroscopic polarization in III-V nitride alloy heterostructures
TL;DR: In this paper, the nonlinear polarization for nitride alloys of arbitrary composition was calculated, and the bound sheet charge induced by polarization discontinuity at the interfaces between different alloy and binary (epi) layers.
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Optical constants of epitaxial AlGaN films and their temperature dependence
D. Brunner,H. Angerer,E. Bustarret,F. Freudenberg,R. Höpler,Roman Dimitrov,Oliver Ambacher,Martin Stutzmann +7 more
TL;DR: In this paper, the authors studied the dependence of the absorption edge and the refractive index of wurtzite AlxGa1−xN films on temperature and composition using transmission and photothermal deflection spectroscopy.
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Defect structure of epitaxial GaN films determined by transmission electron microscopy and triple-axis X-ray diffractometry
T. Metzger,R. Höpler,E. Born,Oliver Ambacher,Martin Stutzmann,R. Stömmer,M. Schuster,H. Göbel,Silke Christiansen,Martin Albrecht,Horst P. Strunk +10 more
TL;DR: In this article, the correlation lengths and dislocation densities of hexagonal GaN grown by metallorganic chemical vapour deposition on c-plane sapphire are determined by transmission electron microscopy and triple-axis X-ray diffractometry.
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Undoped AlGaN/GaN HEMTs for microwave power amplification
L.F. Eastman,V. Tilak,Joseph A. Smart,B.M. Green,E.M. Chumbes,Roman Dimitrov,Hyungtak Kim,Oliver Ambacher,Nils Weimann,T. Prunty,M. J. Murphy,William J. Schaff,James R. Shealy +12 more
TL;DR: In this paper, a two-dimensional electron gas (2DEG) is induced using the strong spontaneous and piezoelectric polarization inherent in the AlGaN/GaN structures, and three-dimensional nonlinear thermal simulations are made to determine the temperature rise from heat dissipation in various geometries.
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Band gap, electronic structure, and surface electron accumulation of cubic and rhombohedral In 2 O 3
Phil D. C. King,Tim D. Veal,Frank Fuchs,Ch. Y. Wang,D. J. Payne,A. Bourlange,H. Zhang,Gavin R. Bell,V. Cimalla,Oliver Ambacher,Russell G. Egdell,Friedhelm Bechstedt,Christopher F McConville +12 more
TL;DR: In this paper, the bulk and surface electronic structure of cubic bixbyite and rhombohedral polymorphs was investigated from x-ray photoemission spectroscopy measurements and density functional theory calculations.