아래와 같이 콜로퀴움을 개최하오니 많이 참석해 주시기 바랍니다. 4시부터 2층 라운지세미나실에 다과를 준비하오니 많은 참석 부탁드립니다 아 래 1. 제 목: Nanoimprint lithography and its application to nano-structured optical devices 2. 연 사: 이 기 동 박사 (LG 전자기술원) 3. 일 시: 2007년 10월 12일(금) 오후4:30 4. 장 소: 물리학과세미나실(31355호실) 5. 초 록: Nanoimprint lithography (NIL) is being considered as one of the strongest candidates for the next-generation lithography which can replace the current optical lithography. It is also expected to be widely used in the industry including semiconductor, display, and storage media etc. Among the wide spectrum of application fields, NIL is expected to find its short-term application in the area of optical devices with nanoscale structures. In this talk, with the introduction to the NIL technology, two optical devices with nano-scale subwavelength structure fabricated by NIL will be discussed. (1) Wire grid polarizer (WGP) is one of key optical components for projection displays with liquid crystal micro-display. Although WGP with 140 nm pitch is commercially available now, it still poses a problem with low extinction ratio (ER) for blue color. Since the ER can be increased by reducing the pitch, fabrication of a WGP with 100 nm pitch was attempted by NIL. We successfully developed thermal nanoimprint and aluminum dry etching processes. Fabricated WGPs showed twice higher ER than 140 nm pitch one. (2) Photonic crystal (PC) structures on LED have been known to enhance the light extraction significantly. Although e-beam lithography has been used for the proof of principle, it is far from real production method. We applied thermal NIL to fabricate PC structures in p-GaN layer of green LED. To identify the PC effect, two structures were fabricated and compared. One structure makes the green light of 525 nm wavelength fall within the photonic band gap (PBG) while the other puts it outside of PBG. The former structure showed 10- fold increment of photoluminescence compared to LED without PC structures, while the latter showed only 6-fold increment