Publications

Fatigue of Polycrystilline Silicon in MEMS Devices

Angela S. Choy
Kyriakos Komvopoulos
Albert P. Pisano
Roger T. Howe
1999

A clear understanding of the mechanical properties of the structural materials used in MEMS devices is critical in the design and reliability analysis of these devices. However, it cannot be assumed that macroscale and microscale devices have the same behavior. Macroscale fatigue mathods cannot accurately predict the behavior of microscale devices because at microscale sizes, the structure size is on the same order of magnitude as the grain size of the material. Also, grain boundaries, environmental, and facrications effects, which are negligible on the macroscale, may be significant on...

Flexible Supercapacitors Based on Micro/Nanofibers

Caiwei Shen
Liwei Lin
Bryan McCloskey
Van Carey
2018
Flexible energy storage components are indispensable in the field of flexible electronicsSupercapacitors featuring high power density, fast charge/discharge rate, long cycle life, and safe operation are desirable devicesMicro/nanofiber-based electrode materials, fabrication processes, and device configurations are investigated towards flexible supercapacitors ...

Enclosed Microfluidic Platform Realizing Enhanced Stem-cell Survival (EMPRESS)

Yue Zhang
Matthew V. Tirrell
Albert P. Pisano
Tejal A. Desai
2011

Here we present a microfluidic culture platform for enhancing single stem cell survival. Traditional plate culture is inadequate for large scale single cell studies because of (1) less than 40% single stem cell survival leading to (2) possible inaccuracies in the biostatistics in single cell studies from lack of sufficient data. This platform mitigates these issues by doubling overall survival rates as well as increasing the available data points by...

Electrochemical Approaches to Renewable Energy

Peter Lobaccaro
Joel Ager
Roya Maboudian
Alexis Bell
Ali Javey
2016
Renewable energy is becoming an increasingly important component of the world’s energy supply as the threat of global warming continues to rise. There is a need to reduce the cost of this renewable energy and a future challenge to deal with the strain intermittent power sources like renewables place on the power grid. In this dissertation, electrochemistry is harnessed to address possible solutions to both of these issues. First, it is used to develop a low...

Evaporation-Driven Fast Crystallization of 3D Micro- and Nano-particle Assemblies via Micro Mechanical Systems

Sun Choi
Albert P. Pisano
Tarek I. Zohdi
Liwei Lin
Ming C. Wu
2012
Fast crystallization of solid-phase materials in liquid medium is a crucial prerequisite to achieve the aims of a number of applications for micro-, nano-manufacturing, bio-chemical sensing technology and fundamental colloidal scienceCorresponding mechanical systems for those applications are required to accommodate and take advantage of the virtue of multi-phase (liquid, gas, and solid phases) flow phenomenon to accomplish “...

Excimer Laser Annealing of Silicon Germanium for MEMS Applications

Carrie W. Low
Roger T. Howe
Tsu-Jae King
2004
Poly-SiGe is a promising material for modular integration of MEMS with electronics due to its low process thermal budget. Poly-SiGe can be deposited on top of standard CMOS electronics in a LPCVD reactor as a replacement of poly-Si as MEMS structure material. Deposition temperature at 450 °C along with 550 °C rapid thermal annealing can result good electrical and mechanical properties of the SiGe film. SiGe films deposited at lower temperature have degradations in mechanical properties, such as high ...

Electromagnetic Energy Harvester for Sensors on Overhead Power Distribution Lines

Zhiwei Wu
Liwei Lin
Richard M. White
Dennis Lieu
2020

The electric grid began its service over 100 years ago and accumulated many safety concerns regarding its infrastructure and nearby environment. The wireless sensor network has been deployed to monitor the condition of both the grid infrastructure and environment, and non-interrupted power sources with minimal maintenance has been an engineering challenge. Here, design of an inexpensive and durable electromagnetic energy harvester coupled with the magnetic field from the power line conductors for powering the wireless...

Effects of Abrupt Changes in Microfluidic Geometry on Complex Biological Fluid Flows

Shelly Gulati
Dorian Liepmann
Susan J. Muller
Andrew J. Szeri
David Saloner
David Trebotich
2006
Direct measurement techniques are employed to quantify the kinematics of λ-DNA flows in three microfluidic components with abruptly changing geometries. Flow through these geometries subjects the fluid to large spatial gradients in velocity, leading to viscoelastic effects. The effects on DNA transport in microscale flows are significant because flow behavior may be influenced by elasticity of individual molecules,...

Development of a Free-Space Optical Switch for Fiber Communications Based on Actuated, Silicon Surface-Micromachined Mirrors

Alois Friedberger
Richard S. Muller
1996
Optical communication networks require switches for fiber links. Free-space optical switches have the potential of high coupling efficiencies and are investigated for fabrication by silicon surface-micromachining. Due to batch processing, this technology can provide large...

Design and Analysis of Closed-loop Controlled Parallel-Plate Electrostatic MicroGrippers

Patrick Breckow Chu
Kristofer S.J. Pister
1994

This work describes the design and analysis of a class of sub-millimeter scale grippers. These electrostatically-driven devices are fabricated from polysilicon using an IC-based surface micromachining process and have been designed to handle objects...