Electromechanical oscillators Alfredo D. Bobadilla

1. Electromechanical oscillators Alfredo D. Bobadilla

2. What is an electromechanical oscillator (or resonator) ? • An element of the electrical circuit experiences movement or oscillations. • Notice how the electrical current depends on the capacitor displacement. • In the system shown, the electrical behavior depends on mechanical properties.

3. Commercialization of micro electromechanical oscillators • Acceleration sensors for automobile air bag control • Gyroscopes for automobile driving control • Pressure sensors for blood, tire, etc. Schematic of the gyro’s mechanical structure. Photograph of mechanical sensor. The ADXRS gyros include two structures to enable differential sensing in order to reject environmental shock and vibration.

4. Other applications Wireless communication Mechanical resonators as filters in RF circuits 100x power reduction 100x size reduction 10x improvement in spectral eff. & BW AFM images of DNA-based nanostructures AFM 165nm scale bars = 100nm

5. The carbon nanotube electromechanical oscillator A tunable nanoscale resonator • When a voltage is applied between the tube and the underlying • plate, electrostatic force attracts the tube to the plate. • An alternating voltage sets up vibration as the tube is alternately • attracted and repelled. • A static voltage applied at the same time increases the tension on • the tube, changing its frequency of vibration just as tightening or • loosening a guitar string changes its pitch. • The entire assembly of tube and plate behaves as a transistor, so • the tube's motion can be read out by measuring the current flow. V. Sazonova et al., Nature (2004).

6. The carbon nanotube electromechanical oscillator Fabrication process Dielectrophoretic assembly J. Chung et al, Langmuir, 2004. B. Witkamp et al, Nano Lett., 2006.

7. The carbon nanotube electromechanical oscillator Theoretical framework B. Witkamp, M. Poot, and H. S. J. van der Zant, Nano Lett., 2006.

8. Performance improvement at nanoscale Mass spectrometer: Ultra high surface/volume ratio → excellent surface collection Ultra small mass → exploit fo sensitivity to mass loading Massive array → very wide dynamic range Calorimeter: Ultra low thermal capacity → exploit fo sensitivity to ∆T Massive array → extends linearity to very wide dynamic range Ultra small size → very fine pixel size as IR imager

10. THANKS!

11. G2 Rebuttal:Nano electromechanical oscillators Alfredo Bobadilla

12. Nano electromechanical oscillators – ‘Rebuttal’ • Comment: “Did not describe the theoretical part of the presentation” • Answer: The theoretical part was explained during the lecture. In essence, the “beam equation” (classical mechanics) is still useful for analyzing bending-mode vibrations in a carbon nanotube longer than ~0.5um. Research work in the nonlinear regime and the quantum regime has just began very recently. • Comment: “Text was small and hard to locate on each slide” • Answer: I’ll improve that next presentation. • Comment: “current or potential applications of such ‘nano’ electromechanical oscillators should have been shown” • Answer: The potential applications of nano electromechanical oscillators is shown in the slides and was described during the lecture. It was shown nanotube resonators can be incorporated as the sensing element for improving the performance in mass spectrometry and in calorimetry. Alfredo D. Bobadilla

13. G1Electro-Mechanical OscillatorsReview Edson P. Bellido Sosa

14. The presenter describe how a EM oscillator works and the basic equations that rules its movement . He explain how a change in a parameter, lets say the voltage on the system, can affect the overall functioning of the device, and how researcher are taking advantage of these behavior to fabricate consumer devices

15. He has explained the fabrication process and how a carbon nanotube based oscillator works, and how they can tune the bending mode vibration by changing the gate applied voltage and how they can measure the bending modes using changes in the conductivity of the carbon nanotube A comparison of the carbon nanotube oscillator and the current oscillator used on the industry, in terms of performance and cost would have been helpful. Further research is needed specially in the large scale integration process since there is no an high throughput technique to create arrays of carbon nanotube oscillators and other nano-devices.

16. G3Review: Electromechanical Oscillators By Mary Coan 2/12/2010

17. Review • Overall the presentation was decent • Described • Current applications of EN oscillators • CNT EM oscillator using various sources and diagrams • Improvements to the performance • Did not describe the theoretical part of the presentation • Showed many equations with out listing parameters • No physical description of the diagrams

18. Review • Overall style of the Presentation was lacking • Text was small and hard to locate on each slide • Some of these things may have been addressed during the actual presentation. However just looking at the presentation online I had a hard time understanding what each slide represented and the contents of each slide.

19. G4Summary and review ‘Electromechanical oscillators’ Diego A Gomez-Gualdron

20. An electromechanical oscillator circuit The distance between the plates of the capacitor varies with time, therefore changing the capacitance, which in turn affect the behavior of the circuit giving it an oscillatory behavior Figure .1

21. Promising application of a nanotube in a nanocircuit • A voltage in generates a charge in • As a result the nanotube is pushed downwards. • Bending the nanotube alter the charge once again, ending up in oscillatory motion with a frequency depending on the tension forces in the nanotube. Nature431, 284-287 (16 September 2004) | doi:10.1038/nature02905 The oscillatory motion of the nanotube, alterates the capacitance in cyclic-fashion analogous to the macroscale circuit in the fig 1.

22. Additional Review • A number of applications were shown for electromechanical oscillators. However, I am not sure if the scale of those examples is in the nanorange. If so, current or potential applications of such ‘nano’ electromechanical oscillators should have been shown.

23. G5 Review Electromechanical Oscillators by Norma Rangel

24. Electromechanical oscillatorsby Alfredo D. Bobadilla • Alfredo show the basic concepts of electromechanical oscillators , with examples of how these devices are being implemented in current technologies in the market, alternative applications and a couple of papers about state of the art electromechanical oscillators using nanotubes and origami DNA. • My suggestion for Alfred presentation is to put more emphasis on the experimental work than being too deep on the theoretical framework

25. G6 Review Electromechanical Oscillators by Jung Hwan Woo

26. Review • Overall, the presentation needs improvements • Improved presentation skill will help deliver the idea in a more effective manner • The use of larger fonts and images will make it easier for the audience to better visualize and understand the concept • A better introduction may attract the audience into the subject and the presentation. • The pace can be increased to contain more information. The information on the subject was a bit too little for a 30-minute presentation Jung Hwan Woo

27. Application • What NEMS applications are there, which take advantage of the electromechanical oscillator other than the carbon nanotube application? • What are the advantage of reducing the size of the device in MEMS/NEMS applications? Is there any downside to it? Jung Hwan Woo