Liwei Lin (Advisor)

Research Advised by Professor Liwei Lin

Lin Group:  List of Projects | List of Researchers

Thin Film Encapsulation Methods for Large Area MEMS Packaging

Armon Mahajerin
Liwei Lin
Dorian Liepmann
Tsu-Jae King Liu
2012

The past thirty years have seen rapid growth in products and technologies based on microelectromechanical systems (MEMS). However, one of the limiting factors in commercializing MEMS devices is packaging, which can be the most costly step in the manufacturing process. A MEMS package must protect the movable parts of the device while allowing it to interact with its surroundings. In addition, the miniaturization of sensors and actuators has made it possible to integrate MEMS fabrication with that of integrated circuit (IC) processing. Due to the varying requirements for different...

Cellular Mechanotransduction via Microfabricated Post Arrays

Adrienne Higa
Liwei Lin
Song Li
Dorian Liepmann
2012

Substrate-based biophysical cues, which interact with cells through mechanotransductive pathways, influence many biological processes and cellular behaviors. By leveraging microfabrication techniques, this work aims to build biophysical stimuli into cellular substrates through discrete microtopographic features to study cellular responses. Here, uniform and gradient arrays of circular microposts have been geometrically tuned to change the apparent rigidity of a substrate and the placement of available cellular attachment sites. Three areas of cellular interaction with these micropost...

Nanomaterial Synthesis and Integration for Sensor and Energy Applications

Heather Chiamori
Liwei Lin
Samuel S. Mao
John Clarke
Oscar D. Dubo ́n
2012

Nanostructures have unique properties that will be leveraged for next generation sensor and energy applications: large surface-to-volume ratios, increased sensitivity at lower input power levels, and higher current densities all contribute to increased functionality of nano- structure devices. The synthesis and integration of carbon-, metal-, and metal oxide-based nanostructures for sensor and energy applications are studied with the goal of nano-to-micro devices utilizing well-established micro- and nano-fabrication tools and techniques: (1) self- assembled, integrated carbon...

Electrospun Direct-write Multi-functional Nanofibers

Jiyoung Chang
Liwei Lin
Albert P. Pisano
2012

Multi-functional fibers by means of direct-write near-field electrospinning process have been developed for versatile applications on a wide variety of substrates, including flexible ones. Several mask-less lithographoy techniques have been established by using the direct- write fibers in dry etching, wet etching and lift-off processes. By selecting the proper functional materials, electrospun direct-write fibers have been demonstrated in prototype working devices, such as large array piezoelectric nanogenerators made of polymeric PVDF (Polyvinylidene fluoride) and direct-write micro...

Polymer Microfluidic Device for High-throughput Single-cell Encapsulation, Lysis, and Biological Assay

Timothy Brackbill
Albert P. Pisano
Liwei Lin
Amy Herr
2012

Single cell analysis is the present and future of biological research. It’s becoming clear that sub-populations of cells within a larger group can often be the culprit for diseases or malfunctions. In this work we aim to provide a tool that allows biological researchers to better analyze single cells within cell populations by removing the barrier to observing analytes contained within the cell’s membrane. By providing physical access to the intracellular compounds in a single cell, we can analyze individual cells for levels of analytes that were previously only available through...

MEMS Materials and Temperature Sensors for Down Hole Geothermal System Monitoring

Sarah Wodin-Schwartz
Albert P. Pisano
Liwei Lin
2013

The advancement of renewable energy technologies is critical due to the unsustainable nature of currently used energy sources and the need to meet increasing energy demands. A broad and diverse energy plan is important for long term energy independence and stability. Geothermal energy sources including hydrothermal systems and enhanced geothermal systems (EGS) should play a key role in this energy plan. Geothermal energy is the most reliable, currently developed, schedulable alternative energy source. It is estimated that improvements in these systems have the potential to...

Nanomaterials Processing Toward Large-scale Flexible/Stretchable Electronics

Toshitake Takahashi
Ali Javey
Tsu-Jae King Liu
Liwei Lin
2013

In recent years, there has been tremendous progress in large-scale mechanically flexible electronics, where electrical components are fabricated on non-crystalline substrates such as plastics and glass. These devices are currently serving as the basis for various applications such as flat-panel displays, smart cards, and wearable electronics.

In this thesis, a promising approach using chemically synthesized nanomaterials is explored to overcome various obstacles current technology faces in this field. Here, we use chemically synthesized semiconducting nanowires (...

Copper Oxide by Thermal Oxidation for Electrochemical Cells and Gas Sensors

Kevin Limkrailassiri
Liwei Lin
Costas Grigoropoulos
Roya Maboudian
2013

Advances in electrolytic and gas sensing technologies continue to be driven by careful selection and engineering of materials. Copper oxides—both cuprous oxide, Cu2O, and cupric oxide, CuO—are abundant, environmentally friendly, and highly versatile. An attractive feature unique to both copper oxides is the ease of synthesis through a one-step thermal oxidation of copper foil in ambient environment, yielding various oxide compositions and morphologies according to the oxidation temperature and time. There are many possible applications for the copper oxide...

Aluminum Nitride Sensors for Harsh Environments

Fabian Goericke
Albert P. Pisano
Tsu-Jae King Liu
Liwei Lin
2013

Harsh environment applications include high temperature, pressure and mechanical shock. Aluminum nitride is a strong ceramic material with very good high temperature survivability. It also has piezoelectric properties that can be used for sensing applications and it can be deposited with good control as thin polycrystalline film for the fabrication of micro-electromechanical systems. In this dissertation, optimized deposition parameters for aluminum nitride films and characterization techniques for film stress gradients are investigated. Furthermore, two diff...

Microfluidic Reactors for the Controlled Synthesis of Nanoparticles

E. Yegan Erdem
Albert P. Pisano
Fiona M. Doyle
Liwei Lin
Tsu-Jae King Liu
2013

Nanoparticles have attracted a lot of attention in the past few decades due to their unique, size-dependent properties. In order to use these nanoparticles in devices or sensors effectively, it is important to maintain uniform properties throughout the system; therefore nanoparticles need to have uniform sizes – or monodisperse. In order to achieve monodispersity, an extreme control over the reaction conditions is required during their synthesis. These reaction conditions such as temperature, concentration of reagents, residence times, etc. affect the...