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Full-Text Articles in Engineering
Design Of Ferroelectric Mems Energy Harvesting Devices, Noah T. Blach, Robert A. Lake, Ronald A. Coutu Jr.
Design Of Ferroelectric Mems Energy Harvesting Devices, Noah T. Blach, Robert A. Lake, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
Waste heat is a widely available but little used source of power. Converting a thermal gradient into electricity is conventionally done using the Seebeck effect, but devices that use this effect are naturally inefficient. An alternate approach uses microelectromechanical systems (MEMS) to generate movement and time-varying temperature from a constant temperature gradient. Ferroelectric materials can harvest electricity from moving structures and temperature variations. This concept was realized using traditional silicon microprocessing techniques. A silicon on insulator (SOI) wafer was backside Deep Reactive Ion Etched (DRIE) to form a one mm2 by 7 micron thick silicon/silicon dioxide membrane. Lead zirconate …
A Novel On-Chip Three-Dimensional Micromachined Calorimeter With Fully Enclosed And Suspended Thin-Film Chamber For Thermal Characterization Of Liquid Samples, Benyamin Davaji, Hye Jeong Bak, Woo-Jin Chang, Chung-Hoon Lee
A Novel On-Chip Three-Dimensional Micromachined Calorimeter With Fully Enclosed And Suspended Thin-Film Chamber For Thermal Characterization Of Liquid Samples, Benyamin Davaji, Hye Jeong Bak, Woo-Jin Chang, Chung-Hoon Lee
Electrical and Computer Engineering Faculty Research and Publications
A microfabricated calorimeter (μ-calorimeter) with an enclosed reaction chamber is presented. The 3D micromachined reaction chamber is capable of analyzing liquid samples with volume of 200 nl. The thin film low-stress silicon nitride membrane is used to reduce thermal mass of the calorimeter and increase the sensitivity of system. The μ-calorimeter has been designed to perform DC and AC calorimetry, thermal wave analysis, and differential scanning calorimetry. The μ-calorimeter fabricated with an integrated heater and a temperature sensor on opposite sides of the reaction chamber allows to perform thermal diffusivity and specific heat measurements on liquid samples with same device. …
6.4 Ghz Acoustic Sensor For In-Situ Monitoring Of Afm Tip Wear, T.J. Cheng, Jun Hyun Han, Michael Ziwisky, Chung-Hoon Lee, S.A. Bhave
6.4 Ghz Acoustic Sensor For In-Situ Monitoring Of Afm Tip Wear, T.J. Cheng, Jun Hyun Han, Michael Ziwisky, Chung-Hoon Lee, S.A. Bhave
Electrical and Computer Engineering Faculty Research and Publications
This paper demonstrates an acoustic sensor that can resolve atomic force microscopy (AFM) tip blunting with a frequency sensitivity of 0.007%. The AFM tip is fabricated on a thin film piezoelectric aluminum nitride (AlN) membrane that is excited as a film bulk acoustic resonator (FBAR). We demonstrate that cutting 0.98 μm off of the tip apex results in a resonance frequency change of 0.4MHz at 6.387GHz. This work demonstrates the potential for in-situ monitoring of AFM tip wear.
Nano-Electromechanical Zero-Dimensional Freestanding Nanogap Actuator, Jun Hyun Han, Norimasa Yoshimizu, T.J. Cheng, Michael Ziwisky, S.A. Bhave, A. Lal, Chung-Hoon Lee
Nano-Electromechanical Zero-Dimensional Freestanding Nanogap Actuator, Jun Hyun Han, Norimasa Yoshimizu, T.J. Cheng, Michael Ziwisky, S.A. Bhave, A. Lal, Chung-Hoon Lee
Electrical and Computer Engineering Faculty Research and Publications
Micromachined free standing nanogap with metal electrodes is presented. The gap size is as small as 17 nm, and can be reduced further with electrostatic or piezoelectric actuation. The nanoscale gap is fabricated by industrial standard optical lithography and anisotropic wet chemical Si etching. Electron transport between the metal electrodes with optical stimulus enhancing photon-electron coupling (plasmon) is presented.
Dependence Of The Performance Of Single Photon Avalanche Diodes On The Multiplication Region Width, David A. Ramirez, Majeed M. Hayat, Mark A. Itzler
Dependence Of The Performance Of Single Photon Avalanche Diodes On The Multiplication Region Width, David A. Ramirez, Majeed M. Hayat, Mark A. Itzler
Electrical and Computer Engineering Faculty Research and Publications
The dependence of the performance of separate-absorption-multiplication (SAM) single-photon avalanche diodes (SPADs) on the width of the multiplication region is theoretically investigated. The theory is applied to SAM SPADs with InP homojunction multiplication regions and InAlAs-InP heterojunction multiplication regions. In both cases the absorber layer is InGaAs. Two scenarios for the dark counts are considered: (i) low-temperature operation, when the number of dark carriers is dominated by field-assisted mechanisms of band-to-band tunneling and tunneling through defects; and (ii) room-temperature operation, when the number of dark carriers in the multiplication region is dominated by the generation/recombination mechanism. The analysis utilizes a …