| AVS 54th International Symposium | |
| MEMS and NEMS | Monday Sessions |
| Session MN-MoA |
| Session: | Materials Processing, Characterization and Fab Aspects |
| 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. Kruzelecky, MPB Communications Inc. J. Margot, Université de Montréal, Canada P. Laou, Defence R and D Canada-Valcartier S. Paradis, Defence R and D Canada-Valcartier |
| Correspondent: | Click to Email |
At a transition temperature of Tt = 68 °C, thermochromic vanadium dioxide (VO2) smart coatings undergo a reversible semiconductor-to-metallic phase transition (SMT). This phase transition is accompanied by an important modification of the electrical resistivity and optical properties in the infrared region. The Tt can be controlled by doping the coating with donorlike or acceptor like centers. In addition, the SMT of VO2 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 various switching applications. Recently, we have successfully fabricated micro-optical switch device based on semiconducting and transmitting (on) state to the metallic and reflecting (off) state of W(1.4 at. %)-doped VO2 operating at λ = 1.55 µm and driven by an external voltage.1 This device exhibited an extinction ratio (on/off) as high as 28 dB. In addition, the electro-transmittance switching modulation of the device was demonstrated at 1.55 µm by controlling the SMT with superposition of a dc and ac switching voltages. In this paper, we present our recent results on the mico-fabrication and characterization of stationary optical shutter device based on transmittance switching (on/off) of W-doped VO2 active layer. This shutter consists on 16 smart micro-slit arrays, which can be controlled individually by an external voltage (either a dc or ac switching voltage). This control allows to perform any desirable on-off combination of the micro-optical slits. The starting W-doped VO2/Al2O3 was synthesized by reactive pulsed laser deposition. The micro-slit arrays were patterned by photolithography and plasma etching, whereas Au/NiCr electrical contacts were integrated on the top of the micro-slit by means of the lift-off process. The response of the device was investigated at 1.55 µm by controlling individually the transmittance switching of the active slits by an external voltage. The results show clearly that this device can be used as stationary Hadamard shutter to increase the sensitivity of infrared spectrometer.
1 M. Soltani, M. Chaker, E. Haddad, R. V. Kruzelecky, and J. Margot, J. Vac. Sci. Technol. A 25(4), Jul/Aug (2007).