Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 26: Layer Properties: Electrical, Optical, and Mechanical Properties
DS 26.10: Talk
Wednesday, March 18, 2015, 17:30–17:45, H 2032
Significant Band Gap Narrowing of ALD Deposited ZnO:Al by Correlated Spectroscopic Ellipsometry, Photoluminescence and Spectrophotometry — •Michael Latzel1,2, Manuela Göbelt1, Gerald Brönstrup1,3, Cornel Venzago4, Sebastian W. Schmitt1, and Silke H. Christiansen1,3 — 1Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1/Bau 24, Erlangen, Germany — 2Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Institute of Optics, Information and Photonics, Staudtstr. 7/B2, Erlangen, Germany — 3Helmholtz Center Berlin for Energy and Materials, Hahn-Meitner-Platz 1, Berlin, Germany — 4AQura GmbH, Rodenbacher Chaussee 4, Hanau-Wolfgang, Germany
Knowing the dielectric function of a material for optoelectronic applications is essential for efficient device design and simulation. We investigated the contributions of different optical transitions in aluminum doped zinc oxide deposited by atomic layer deposition to a model dielectric function (MDF) over a wide range of photon energy. We found strong evidence for band gap narrowing due to aluminum doping and intrinsic defects and impurities. The derived MDF strongly depends on the actual band structure and therefore describes the dielectric properties very accurately. The presented MDF is solely based on physical parameters, in contrast to empirical models like e.g. widely used Sellmeier equation. This allows determining key electronic parameters like the band gap or even charge carrier lifetimes.