AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP9
Micro-Optical Switch Device Based on Semiconductor-To-Metallic Phase Transition Characteristics of W-doped VO@sub 2@ Smart Coatings

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: M. Soltani, INRS-Energie, Matériaux et Télécommunications, Canada
Authors: M. Soltani, INRS-Energie, Matériaux et Télécommunications, Canada
M. Chaker, INRS-Energie, Matériaux et Télécommunications, Canada
E. Haddad, MPB Communications Inc.
R.V. Kruzelecky, MPB Communications Inc.
J. Margot, Université de Montréal, Canada
Correspondent: Click to Email
Thermochromic vanadium dioxide (VO2) smart coatings undergo a reversible semiconductor-to-metallic phase transition (SMT) at a transition temperature of Tt = 68°C. This phase transition is accompanied by an important modification of the electrical resistivity, optical transmittance and reflectance in the infrared region. The Tt can be controlled by doping the coating with donor-like or acceptor-like centers. In addition, the SMT of VO2 thin films can be controlled by external parameters such as temperature, pressure, photo-carrier injection into a VO2 heterostructure, and an electric field. VO2 smart coatings are thus excellent materials for technological applications such as optical fiber switching devices,@footnote 1@ smart radiator devices for spacecraft,@footnote 2@ all-optical and electro-optical switching devices.@footnote 3@ Recently, we have optimized the reactive pulsed laser deposition (RPLD) parameters to grow either an undoped or metal (W and Ti) doped VO2 smart coatings on large area substrates@footnote 4@ as well as on small area substrates such as ends of cleaved fibers and optical fibers connectors. Also, we were able to control the SMT of the VO2 layers by photo-excitation (i.e., all-optical switching), as well as by an external electric-field (i.e., electro-optical switch). In this paper, we present our recent results on the fabrication and characterization of micro-optical switch device exploiting the semiconductor (on) to metallic (off) states of W-doped VO2 active layers driven by an external voltage. The active layers were synthesized on sapphire substrate by means of RPLD. The micro-optical switch was patterned by photolithography and plasma etching. While the NiCr electrical contacts were patterned by means of the lift-off process. The transmittance switching (on/off) of the fabricated device was investigated at @lambda@ = 1.55 µm as a function of the applied voltage through the NiCr electrical contacts. An extinction ratio (on/off) as high as 20 dB was achieved with this device.@FootnoteText@@footnote 1@M. Soltani, M. Chaker, E. Haddad, R. V. Kruzelecky, and D. Nikanpour, J. Vac. Sci. Technol. A 22, 859 (2004).@footnote 2@R.V. Kruzelecky, E. Haddad, W. Jamroz, M. Soltani, M. Chaker, and G. Colangelo, Proc. SAE, Paper 2005-01-2906 (2005).@footnote 3@M. Soltani, M. Chaker, E. Haddad, and R. V. Kruzelecky, Meas. Sci. Technol.17, 1052 (2006).@footnote 4@M. Soltani, M. Chaker, E. Haddad, R. V. Kruzelecky, and J. Margot, Appl. Phys. Lett. 85, 1958 (2004).