Keon+Jae+Lee
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A KAIST research team developed in vivo flexible large scale integrated circuits
Daejeon, Republic of Korea, May 6th, 2013–-A team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering at KAIST has developed in vivo silicon-based flexible large scale integrated circuits (LSI) for bio-medical wireless communication.
Silicon-based semiconductors have played significant roles in signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited uses in in vivo devices due to incongruent contact with the curvilinear surfaces of human organs. Especially, artificial retinas recently approved by the Food and Drug Administration (refer to the press release of FDA"s artificial retina approval) require extremely flexible and slim LSI to incorporate it within the cramped area of the human eye.
Although several research teams have fabricated flexible integrated circuits (ICs, tens of interconnected transistors) on plastics, their inaccurate nano-scale alignment on plastics has restricted the demonstration of flexible nano-transistors and their large scale interconnection for in vivo LSI applications such as main process unit (MPU), high density memory and wireless communication. Professor Lee"s team previously demonstrated fully functional flexible memory using ultrathin silicon membranes (Nano Letters, Flexible Memristive Memory Array on Plastic Substrates), however, its integration level and transistor size (over micron scale) have limited functional applications for flexible consumer electronics.
Professor Keon Jae Lee"s team fabricated radio frequency integrated circuits (RFICs) interconnected with thousand nano-transistors on silicon wafer by state-of-the-art CMOS process, and then they removed the entire bottom substrate except top 100 nm active circuit layer by wet chemical etching. The flexible RF switches for wireless communication were monolithically encapsulated with biocompatible liquid crystal polymers (LCPs) for in vivo bio-medical applications. Finally, they implanted the LCP encapsulated RFICs into live rats to demonstrate the stable operation of flexible devices under in vivo circumstances.
Professor Lee said, "This work could provide an approach to flexible LSI for an ideal artificial retina system and other bio-medical devices. Moreover, the result represents an exciting technology with the strong potential to realize fully flexible consumer electronics such as application processor (AP) for mobile operating system, high-capacity memory, and wireless communication in the near future."
This result was published in the May online issue of the American Chemical Society"s journal, ACS Nano (In vivo Flexible RFICs Monolithically Encapsulated with LCP). They are currently engaged in commercializing efforts of roll-to-roll printing of flexible LSI on large area plastic substrates.
Movie at Youtube Link: Fabrication process for flexible LSI for flexible display, wearable computer and artificial retina for in vivo biomedical application
http://www.youtube.com/watch?v=5PpbM7m2PPs&feature=youtu.be
Applications of in Vivo Flexible Large Scale Integrated Circuits
Top: In vivo flexible large scale integrated circuits (LSI); Bottom: Schematic of roll-to-roll printing of flexible LSI on large area plastics.
2013.06.09 View 12774 -
Cancer detection from an implantable, flexible LED
Professor Keon Jae Lee
A KAIST research team has developed a new type of biocompatible and bendable GaN LED biosensor.
Daejeon, the Republic of Korea, August 8, 2011—Can a flexible LED conformably placed on the human heart, situated on the corrugated surface of the human brain, or rolled upon the blood vessels, diagnose or even treat various diseases? These things might be a reality in the near future.
The team of Professor Keon Jae Lee (Department of Materials Science and Engineering, KAIST) has developed a new concept: a biocompatible, flexible Gallium Nitride (GaN) LED that can detect prostate cancer.
GaN LED, a highly efficient light emitting device, has been commercialized in LED TVs and in the lighting industry. Until now, it has been difficult to use this semiconductor material to fabricate flexible electronic systems due to its brittleness. The research team, however, has succeeded in developing a highly efficient, flexible GaN LED and in detecting cancer using a flexible LED biosensor.
Prof. Lee was involved in the first co-invention of "High Performance Flexible Single Crystal GaN" during his PhD course at the University of Illinois at Urbana-Champaign (UIUC). This flexible GaN LED biosensor utilized a similar protocol to transfer thin GaN LED films onto flexible substrates, followed by a biocompatible packaging process; the system’s overall potential for use in implantable biomedical applications was demonstrated.
Professor John Roger (Department of Materials Science and Engineering, UIUC) said,
“Bio-integrated LEDs represent an exciting, new technology with strong potential to address important challenges in human health. This present work represents a very nice contribution to this emerging field.”
This paper was published in the online issue of Nano Energy Elsevier Journal (Editor, Prof. Zhong Lin Wang) dated September 16, 2011.
Flexible GaN LED produces blue light.
2011.09.20 View 10907 -
The KAIST & GIT team developed a power generation technology using bendable thin film nano-materials.
Figure description: Flexible thin film nanomaterials produce electricity.
Can a heart implanted micro robot operate permanently?
Can cell phones and tiny robots implanted in the heart operate permanently without having their batteries charged?
It might sound like science fiction, but these things seem to be possible in the near future. The team of Prof. Keon Jae Lee (KAIST, Dept. of Materials Science and Engineering) and Prof. Zhong Lin Wang (Georgia Institute of Technology, Dept. of Materials Science and Engineering) has developed new forms of highly efficient, flexible nanogenerator technology using the freely bendable piezoelectric ceramic thin film nano-materials that can convert tiny movements of the human body (such as heart beats and blood flow) into electrical energy.
The piezoelectric effect refers to voltage generation when pressure or bending strength is applied to piezoelectric materials. The ceramics, containing a perovskite structure, have a high piezoelectric efficiency. Until now, it has been very difficult to use these ceramic materials to fabricate flexible electronic systems due to their brittle property.
The research team, however, has succeeded in developing a bio-eco-friendly ceramic thin film nanogenerator that is freely bendable without breakdown.
Nanogenerator technology, a power generating system without wires or batteries, combines nanotechnology with piezoelectrics that can be used not only in personal mobile electronics but also in bio-implantable sensors or as an energy source for micro robots. Energy sources in nature (wind, vibration, and sound) and biomechanical forces produced by the human body (heart beats, blood flow, and muscle contraction/relaxation) can infinitely produce nonpolluting energy. (Nanogenerator produces electricity by external forces: http://www.youtube.com/watch?v=tvj0SsBqpBw)
Prof. Keon Jae Lee (KAIST) was involved in the first co-invention of “High Performance Flexible Single Crystal Electronics” during his PhD course at the University of Illinois at Urbana-Champaign. This nanogenerator technology, based on the previous invention, utilized the similar protocol of transferring ceramic thin film nano-materials on flexible substrates and produced voltage generation between electrodes.
Prof. Zhong Lin Wang (Georgia Tech, inventor of the nanogenerator) said, “This technology can be used to turn on an LED by slightly modifying circuits and operate touchable flexible displays. In addition, thin film nano-materials (‘barium titanate’) of this research have the property of both high efficiency and lead-free bio compatibility, which can be used in future medical applications.” This result is published in November online issue of ‘Nano Letters’ ACS journal.
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Youtube link: http://www.youtube.com/watch?v=tvj0SsBqpBw
Thin Film Nanogenerator produces electricity by external forces.
2010.11.23 View 14324