Lab name: Micro and Nano Systems Laboratory

Lead professor: Liwei Lin

Location: Mechanical Engineering Department, University of California at Berkeley

Further information:

Lab profile: Liwei Lin, University of California at Berkeley

A new age of manufacturing is enabling mechanical devices to be created at smaller scales than ever thought possible. Such microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) are opening up new mechanical and microfluidic capabilities on the micro- and nanoscale for sensors, actuators, and applications in energy, biomedicine, and other areas.

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Liwei Lin, professor of mechanical engineering at the University of California at Berkeley, co-director of the Berkeley Sensor and Actuator Center (BSAC) and Tsinghua Berkeley Shenzhen Institute (TBSI), has spent his career applying the principles of mechanical engineering to different systems from the micro- to the nanoscale in applications ranging from the biological to fluidic to electronic. He received a BS from National Tsing Hua University in Taiwan and a PhD from UC Berkeley. After graduating, Liwei spent time at BEI Electronics Inc., the National Taiwan University, and the University of Michigan before rejoining UC Berkeley.

Liwei is also the recipient of many awards, co-inventor of 20 MEMS-related patents and serves on the editorial board of numerous journals, including Sensors and Actuators A – Physical.

Materials Today spoke to Liwei Lin about his work…

How long has your group been running?

My group at UC Berkeley has been running since 1999.

How many staff make up your group?

There are over 20 people in my group at the current time. Since 1996, I have supervised numerous PhD and MSc students.

What are the major themes of research in your group?

The major themes in my research group are microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). Our work spans nanotechnology; design and manufacturing of microsensors and microactuators; development of micromachining processes by silicon surface/bulk micromachining; micro-molding processing; mechanical issues in MEMS including heat transfer, solid/fluid mechanics and dynamics.

How and why did you come to work in these areas?

I have been working in these areas since I was a graduate student almost 30 years ago, starting with the use of mechanical designs and microfabrication for MEMS, including microsensors and microactuators, mechanical filters, and silicon-processed microneedles. I have also been interested in the development of micromachining processes by silicon surface/bulk micromachining micromolding and 3D printing processes, as well as mechanical issues in MEMS such as heat transfer, solid/fluid mechanics, and dynamics.

More recently, I have been working on nanotechnology-based systems, such as carbon nanotubes, graphene, and nanofibers, developing process technologies such as near-field electrospinning for energy and sensing applications.

What has been your highest impact/most influential work to date?

My previous work on high-energy conversion efficiency direct-write piezoelectric polymeric nanogenerators [1], near-field electrospinning [2], silicon-processed microneedles [3], and 3D printed wireless sensors and microfluidics systems [4] has had the highest impact.

What facilities and equipment does your group have?

Our University has a state-of-art nanofabrication lab with all the necessary equipment in the cleanroom to make integrated circuitry and other devices. We have also built-up our own fabrication equipment such as a near-field electrospinning setup.

Do you have a favorite piece of kit or equipment?

Our near-field electrospinning setup is my personal favorite.

What is the key to running a successful group?

I think encouraging and exploring new ideas is important, as well as being open-minded for different ideas.

How do you plan to develop the group in the future?

I would like to continue exploring new directions and new areas.

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Key publications

1. Chieh Chang, Van H. Tran, Junbo Wang, Yiin-Kuen Fuh and Liwei Lin. Direct-Write Piezoelectric Polymeric Nanogenerator with High Energy Conversion Efficiency. Nano Letters 10 (2010) 726-731.

2. DaoHeng Sun, Chieh Chang, Sha Li and Liwei Lin. Near-Field Electrospinning. Nano Letters 6 (2006) 839-842.

3. Liwei Lin and A.P. Pisano. IC-Processed Microneedles. IEEE/ASME Journal of Microelectromechanical Systems 8 (1999) 78-84.

4. Sung-Yueh Wu, Chen Yang, Wensyang Hsu, and Liwei Lin. 3D Printed Microelectronics for Integrated Circuitry and Passive Wireless Sensors. Microsystems & Nanoengineering 1 (2015) 15013.