1. 제목 : Fabrication of Releasable and Fully Formed GaN LED and Single Crystal Silicon (MOSFET) Devices and Their Deterministic Assembly on Foreign Substrates

2. 연사 : Tae-il Kim Ph.D.

 Materials Science and Engineering, Univ. of Illinois at Urbana-Champaign

3. 일시 : 2011년 7월 14일 (목) 10:30-11:30

4. 장소 : 301동 1512-2호 세미나실

5. 내용 : A new class of thin and releasable single crystal silicon device and inorganic LED technology enables integration of high performance electronics and optoelectonics on nearly any type of substrate. Fully formed metal oxide semiconductor field effect transistors with thermally grown gate oxides and integrated circuits constructed with them demonstrate the ideas in devices mounted on substrates ranging from flexible sheets of plastic, to plates of glass and pieces of aluminum foil. Systematic study of the electrical properties indicate field-effect mobilities of  ~710 cm2/V∙sec, subthreshold slopes less than 0.2 V/decade and minimal hysteresis, all with little or no dependence on the properties of the substrate due to bottom silicon surfaces that are passivated with thermal oxide. Furthermore, transferrable, bright, and thin micro GaN LEDs and their arrays on flexible substrate were presented. To obtain high performance, a high-temperature process (i.e., 500 ºC) for ohmic contact enhancement was performed on sapphire substrate. Exposing the sapphire and GaN interface to a laser (KrF, YaG), the GaN layer is lifted off from the sapphire substrate and now can be picked up and transferred to a foreign substrate. LEDs fabricated via this technique show high efficiency and luminescence compared to thin film organic LEDs. The schemes presented here require only interconnect metallization to be performed on the finalsubstrate where devices are printed, thereby minimizing the need for any specialized processing technology, with important consequences in large area electronics for display systems, flexible/stretchable electronics or other non-wafer based devices and bio-implantable devices.

6. 약력 : Dr Tae-il Kim was born in Daegu, South Korea in 1977. He earned his BS degree from Sungkyunkwan University in 2003 and his PhD degree from SNU in 2009. He has been working on a number of unconventional patterning methods and their application in optical devices (wire-gird polarizers) and biomimetic structures (superhydrophobic surfaces and gecko-like hairy surfaces). Currently, he is a postdoctoral researcher at the University of Illinois at Urbana-Champaign (UIUC), working on a bendable GaN micro-LED and fully formed silicon transistors for bio-integrated devices and optogentics. He has written 23 papers for peer-reviewed journals.

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