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Title: Optical properties of anodically degraded ZnO

We discuss the optical properties of non-degraded and anodically degraded boron-doped zinc oxide (ZnO:B) deposited by low-pressure chemical vapour deposition on soda-lime glass. The optical model used to simulate the infrared reflectance in the wavelength range between 1.2 and 25 μm is based on the Maxwell-Garnett effective-medium theory. The model is sensitive to the conditions at the grain boundaries of the investigated polycrystalline ZnO:B films. We confirm that the presence of defect-rich grain boundaries, especially after degradation, causes a highly resistive ZnO:B film. Furthermore, indications of a degraded zinc oxide layer next to the ZnO:B/glass interface with different refractive index are found. We present evidence for the creation of oxygen vacancies, based on Raman investigations, which correlate with a shift of the optical absorption edge of the ZnO:B. Investigations with scanning and transmission electron microscopy show microvoids at the grain boundaries after anodic degradation. This indicates that the grain/grain interfaces are the principle location of defects after degradation.
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Bosch Solar Energy AG, Robert-Bosch-Straße 1, D-99310 Arnstadt (Germany)
  2. Robert Bosch GmbH, Robert-Bosch-Platz 1, D-70839 Gerlingen (Germany)
  3. TU Ilmenau, Zentrum für Mikro- und Nanotechnologien (ZMN), Gustav-Kirchhoff-Straße 7, D-98693 Ilmenau (Germany)
  4. Centre Suisse d'Electronique et Microtechnique (CSEM), PV-center, Rue Jacques-Droz 1, CH-2002 Neuchâtel (Switzerland)
  5. École Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory, Rue de la Maladière 71, CH-2000 Neuchâtel (Switzerland)
Publication Date:
OSTI Identifier:
22277954
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BORON; CHEMICAL VAPOR DEPOSITION; CRYSTAL DOPING; GRAIN BOUNDARIES; INTERFACES; LAYERS; OPTICAL MODELS; OXYGEN; POLYCRYSTALS; RAMAN SPECTRA; REFRACTIVE INDEX; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; VACANCIES; ZINC OXIDES