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ECE Department - UPR-Mayaguez |
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Prof. Nelson Sepulveda |
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Research |
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My current research interests are in vanadium dioxide (VO2) thin films. Recently, we reported the first studies of the mechanical properties of this material during its insulator-to-metal transition.
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Current Research |
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· Explore the use of VO2 for microwave switches |
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PLD System for VO2 deposition. click the picture to see a short video. |
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The phase transition in VO2 can be used to tune resonant frequencies ...UP and DOWN!!!! |
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What am I seeing in the video?? This is the effect of the phase transition on the deflection of a laser on a VO2 coated Si cantilever. Look at the temperature and the upper laser spot (the bottom one is just a reflection from the chamber window). When the temperature reaches approximately 68 C (where the phase transition in VO2 occurs), the laser spot moves!!! If you notice carefully, about 7 degrees before and after 68 C the laser spot does not move, which indicates that the movement is due to the phase transition in VO2. To make it more interesting, the uncoated Si cantilever was 1μm thick, and the VO2 coating was only 100 nm!! |
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LASER SPOT |