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Title: Structural enhancement of ZnO on SiO{sub 2} for photonic applications

Multi-layer thin films are often the basis of photonic devices. Zinc oxide (ZnO) with its excellent optoelectronic properties can serve as a high quality emitter in structures like microdisks or photonic crystals. Here, we present a detailed study on the enhancement of the structural properties of low-temperature MBE grown ZnO on silica (SiO{sub 2}). By thermal annealing a grain coalescence of the initially polycrystalline layer leads to an enhancement of the electronic structure, indicated by a blue shift of the photoluminescence (PL) signal maximum. Oxygen atmosphere during the annealing process prevents the creation of intrinsic defects by out-diffusion. Pre-annealing deposited SiO{sub 2} capping layers instead obstruct the recrystallization and lead to less intense emission. While thin capping layers partially detach from the ZnO film at high temperatures and cause higher surface roughness and the weakest emission, thicker layers remain smoother and exhibit a significantly stronger photoluminescence.
Authors:
;  [1]
  1. Experimental Physics, University of Paderborn, Paderborn (Germany)
Publication Date:
OSTI Identifier:
22220492
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 3; Journal Issue: 7; Other Information: (c) 2013 © 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DIFFUSION; ELECTRONIC STRUCTURE; LAYERS; MOLECULAR BEAM EPITAXY; PHOTOLUMINESCENCE; POLYCRYSTALS; RECRYSTALLIZATION; SEMICONDUCTOR MATERIALS; SILICA; SILICON OXIDES; THIN FILMS; ZINC OXIDES