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4시 20분부터 제1과학관 31214 e+강의실에서 다과를 준비하오니 많은 참석 부탁드립니다.

아 래

Title: Grain boundary effect in Metal : A journey of discovery from crystal to thin films without grain boundaries

Speaker: Prof. Se-Young Jeong   ( Department of Cogno-mechatronics Engineering, Pusan National University )

Date & Time: Sep. 23 (Wed.) 2015, 4:30 PM 

Place: Natural Science 1,  Room No. 31214

Abstract: It is well known that the resistivity of a metal is governed by electron–phonon scattering at room temperature, and by electron-impurity scattering at low temperatures. However, questions remain regarding the quantitative grain-boundary (GB) effect on the resistivity at room temperature. Upon examination of metal single crystals, we determined the degree to which the resistivity of the metal could be reduced by the elimination of the GB effect. Moreover, the resistivity continued to decrease, finally reaching its minimum value with successive iterations of GB reduction. Our results indicated that this approach works not only in bulk single crystals but also in thin films.
Radio-frequency (RF) sputtering usually produces polycrystalline films with numerous GBs. However, we developed a new method to grow a thin metal film without GBs; the resulting film quality was comparable to that produced using molecular beam epitaxy (MBE). This proposed technique also enables the fabrication of micro/nano-mesh structures of Cu electrodes on polyimide substrates for flexible, transparent conducting electrode (TCE) fabrication via ultraviolet (UV)-lithography and wet over-etching techniques.
Copper may potentially provide an advantage over silver; however, many questions remain with regard to revealing its full potential. Single crystal study may resolve these questions and those related to new materials yet to be discovered. Thus, a great adventure opens up, as we continue to explore the world of single crystals.