Liwei Lin (Advisor)

Research Advised by Professor Liwei Lin

Lin Group:  List of Projects | List of Researchers

MEMS Hydrogel Sensors for pH and Glucose Measurements

Supone Manakasettharn
Albert P. Pisano
Liwei Lin
2008
A new formulation of a pHand a glucoseresponsive hydrogel was developed and then integrated into an interdigitated MEMS sensor. This new hydrogel was characterized for swelling response as well as for impedance response (resistance and capacitance) when used as both a pH and a glucose sensor. The standard pHresponsive hydrogel, which was a copolymer of 2hydroxyethyl methacrylate and...

Mechanical Energy Storage for Self-Destructing Motes and Jumping Microrobots

Joseph Greenspun
Kristofer S.J. Pister
Vivek Subramanian
Liwei Lin
2018
Mechanical energy storage has been studied to enable a self-destructing mote and ajumping microrobot. Just as chemical energy stored in batteries can be used for a widearray of devices, so too can mechanical energy stored in beams. In this work various energystorage elements are designed, fabricated, and tested to create these MEMS systems. As privacy and data security become increasingly important, new means of keeping that data safe must be developed. A MEMS system has been created to allow a wirelessly enabled...

Micro Chemical Vapor Deposition for the Synthesis of Nanomaterials

Qin Zhou
Liwei Lin
Albert P. Pisano
Ali Javey
2011

MEMS (Microelectromechanical Systems) technologies have enabled the construction of a micro chemical vapor deposition (μCVD) system for the synthesis of nanomaterials. By means of localized resistive heating via microheaters, unique capabilities of the μCVD systems have been utilized to synthesize carbon nanotubes and graphene in this work, including fast stabilization of temperature; rapid exchange of gas species; laminar gas flow due to small Reynolds number; small diffusion...

MEMS Aluminum Nitride Technology for Inertial Sensors

Gabriele Vigevani
Albert P. Pisano
Liwei Lin
Ming C. Wu
2011
The design and fabrication of MEMS Inertial Sensors (both accelerometers and gyro-scopes) made of Aluminum Nitride (AlN) is described in this dissertation. The goal of this work is to design and fabricate inertial sensors based on c-axis oriented AlN polycrystalline thin films. AlN is a post-CMOS compatible piezoelectric material widely used for acoustic resonators, such Bulk Acoustic Wave (BAW) and Lamb Wave Resonators(LWR). In this work we develop the design techniques necessary to obtain inertial sensors...

Low-Power, High-Stability FM MEMS Gyroscopes

Yu-Ching Yeh
Bernhard E. Boser
Liwei Lin
2016

With the advantages of small size and low cost, MEMS gyroscopes have been used in a variety of applications such as image stabilization, gaming control, and motion tracking for mobile or wearable devices. One potential application for MEMS gyroscopes is indoor navigation. This minimizes the infrastructure requirements compared with other approaches with electromagnetic reference beacons. However, recent consumer MEMS gyroscopes are still orders away from achieving navigation grade performance.

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Localized Strain Sensing Using High Resolution, Highly-sensitive MEMS Resonant Strain Gauges

Matthew Wei-Jen Chan
Albert P. Pisano
Liwei Lin
2010

This thesis presents experimental measurements of the first-ever MEMS double ended tuning fork (DETF) resonant strain gauge for localized strain field sensing, successfully bonded to steel by rapid inductive heating. With a gauge length of just 200μm, the presentedMEMS resonant strain gauge enables a high spatial resolution sensor capable of accurately detecting localized strains better than commonly used foil strain gauges, which average strain measurements over much larger areas. The...

Integrated Biophysical Microfluidic Platforms for Pathogen Detection and Single Cell Analysis

Poorya Sabounchi
Luke P. Lee
Albert P. Pisano
Liwei Lin
Daniel A. Fletcher
2007
Pathogen detection is of the utmost importance primarily for health and safety reasons. The most common problem encountered with current pathogen monitoring techniques is the inverse relationship between specificity versus sensitivity and speed. Current tools used for pathogen identification are accurate but require a vast amount of sample preparation time, typically from an experienced operator in a laboratory setting and therefore not suitable for...

Integration of Hydrogels and Plastics into Microfabrication Processes towards a MEMS RF-Interrogated Biosensor

Sebastien Payen
Albert P. Pisano
Liwei Lin
Amy E. Herr
2007
Very inexpensive biosensors capable of monitoring biometrics data of a living organism have long been a goal of biomedical device technology. As such the integration of polymers and plastics are a good solution to achieve low cost and powerless devices. This dissertation presents experimental results on the integration of hydrogels (a class of polymer which swells in water) into microfabrication processes and the development of a new, all-plastic pH sensor. In particular, the work done on oxygen diffusion in hydrogels...

Integrated MEMS Cavity Optomechanical Oscillators for Wireless and Optical Communications

Turker Beyazoglu
Clark T.-C. Nguyen
Ming C. Wu
Liwei Lin
2016
Recent advancements in micro-optical and micro-mechanical resonator technologies haveallowed researchers to exploit coupling between the optical field and mechanical motionin an optical cavity to affect cooling or amplification of mechanical motion. Cooling the mechanical motion of microscale objects has been of high scientific interest, since it facilitates observation and exploration of certain quantum phenomena, e.g., the standard quantum limit of detection. On the other hand, amplification of the mechanical motion...

Highly Scalable Silicon Photonic Switches Based on Waveguide Crossbar with Movable Waveguide Couplers

Sangyoon Han
Ming C. Wu
Richard S. Muller
Liwei Lin
2016
Fast opticalcircuitswitches (OCS) having a large number of ports can significantly enhance the performance and the efficiency of modern data centers by actively rearranging network patternsCommercially available optical switches typically operate with the use of moving mirror arrays. These switches can have port counts...