Structural and optical properties of Zn0.9 Mn0.1 O/ZnO core-shell nanowires des...

• Author(s): Kaydashev, V.E. ; Kaidashev, E.M. ; Peres, M. ; Monteiro, T. ; Correia, M.R. ; Sobolev, N.A. ; Alves, L.C. ; Franco, N. ; Alves, E.
• Date: 2009
• Persistent ID: http://hdl.handle.net/10773/6129
• Origin: RIA - Repositório Institucional da Universidade de Aveiro
• Subject(s): Alumina; Catalysts; Elemental semiconductors; Excitons; Ferromagnetic materials; Ferromagnetic-paramagnetic transitions; Gallium compounds; III-V semiconductors; II-VI semiconductors; Nanofabrication; Nanowires; Paramagnetic materials; Photoluminescence; Pulsed laser deposition; Raman spectra; Red shift; Semiconductor quantum wires; Semimagnetic semiconductors; Silicon; Sintering; Ultraviolet spectra; Wide band gap semiconductors; Zinc compounds
• Document Type: Article
• Language: English

Description

Core-shell ZnO/ZnMnO nanowires on a-Al2O3 and GaN (buffer layer)/Si (111) substrates were fabricated by pulsed laser deposition using a Au catalyst. Two ZnO targets with a Mn content of 10% were sintered at 1150 and 550 °C in order to achieve the domination in them of paramagnetic MnO2 and ferromagnetic Mn2O3 phases, respectively. Cluster mechanism of laser ablation as a source of possible incorporation of secondary phases to the wire shell is discussed. Raman spectroscopy under excitation by an Ar+ laser revealed a broad peak related to the Mn-induced disorder and a redshift in the A1-LO phonon. Resonant Raman measurements revealed an increase in the multiphonon scattering caused by disorder in ZnO upon doping by Mn. Besides the UV emission, a vibronic green emission band assisted by a ∼ 71 meV LO phonon is also observed in the photoluminescence spectra. Core-shell structures with smooth shells show a high exciton to green band intensity ratio ( ∼ 10) even at room temperature. © 2009 American Institute of Physics Partilhar documento na coleção da comunidade Laboratório Associado I3N SANDiE Network of Excellence of the EU FCT-PTDC/FIS/72843/2006