Metal Nano Patterning and Transparent Electrode Fabrication Using Electrospinning and Ion Milling

Abstract

우수한 전기전도도와 낮은 가격 그리고 높은 투명도의 장점을 가지는 나노 패터닝된 네트워크 구조의 구리 투명전극은 Indium doped Tin Oxide (ITO) 필름을 대체할 가장 유망한 후보 중 하나이다. 투명 전극은 디스플레이, 유기 발광 다이오드, 스마트 윈도우, 태양전지 및 터치 스크린과 같은 광전자 장치에 널리 사용된다. 투명 전극의 성능은 일반적으로 면저항 (Rsh)과 광 투과도 (T)에 Trade-off 관계에 의해 결정되지만, 다른 특성들도 투명 전극으로서 재료의 이용가능성에 영향을 미친다. 광 투과율을 손상시키지 않으면서 접합 저항을 제거하는 방법이 투명전극의 성능을 개선할 수 있는 핵심 이슈가 되었다. 본 연구는 전기방사와 낮은 에너지의 아르곤 이온 밀링의 공정을 결합하여 다른 high cost의 patterning process를 사용하지 않고 metal nano pattern을 제조하였다. 본 연구에서 전기 방사된 섬유를 마스크로 사용하여 금속 필름을 투명한 금속 네트워크로 패턴화 하였다. 마스크로 사용된 폴리머 층을 선택적으로 제거하여 3차원 나노구조체를 보다 쉬운 방법으로 구현해냈다. 이는 surface to volume ratio를 높여 추후에 센서나 다양한 분야에 적용 가능할 것이라 사료된다. Pattering에 사용된 나노 섬유를 제거한 후에 높은 형상비와 높은 해상도를 갖는 타겟 금속의 패턴을 얻을 수 있었으며, 이와 같은 방법은 Vacuum process를 사용하여 Solution process의 issue인 organic contamination과 junction resistance을 없애고 High performance의 투명 전극을 다른 high-cost patterning 방법 없이 제작할 수 있다. 본 연구에서 제작된 투명전극(T550 nm = 90 %, Rsh = 6 Ω / □)은 Commercial ITO (T550 nm >90 %, Rsh = 10 Ω/□)와 비슷한 수준으로 이는ITO를 대체할 수 있을 거라 사료된다.|Copper nanopattern networks transparent electrodes, which possess the advantages of good electrical conductivity, low cost, and high transparency, are one of the most promising candidates to replace indium doped tin oxide films. Transparent electrodes are widely used in optoelectronic devices such as displays, organic light emitting diodes, smart windows, solar cells, and touch screens. The performance of a transparent electrode is generally determined by the trade-off relationship of sheet resistance (Rsh) and optical transmittance (T), but other properties also affect the validity of the material as a transparent electrode. A method of removing the junction resistance without compromising the optical transmittance has become a key issue in the improvement performance. Here, we combine electrospinning and low Ar ion bombardment to fabricate metal nanopattern. In this study, metal films are patterned into transparent metal networks by using electrospinning fibers as a mask. By selectively removing the polymer layer used as a mask, a three-dimensional nanostructure was made easier. It is thought to be applicable to sensors and various fields in the future by increasing the surface to volume ratio. After removal of the prepatterned nanofiber, high aspect ratios and high-resolution patterns of target metals are created. After removing the nanofibers used in the patterning, a pattern of a target metal having a high aspect ratio and a high resolution was obtained. This method eliminates organic contamination and junction resistance, which is an issue of the solution process, by using a vacuum process and provides high performance transparency. The electrode can be manufactured without other high-cost patterning methods. The transparent electrode (T550 nm = 90 %, Rsh = 6 Ω / □) fabricated in this study is similar to a commercial ITO (T550 nm > 90%, Rsh = 10 Ω / □) that can replace ITO.; Copper nanopattern networks transparent electrodes, which possess the advantages of good electrical conductivity, low cost, and high transparency, are one of the most promising candidates to replace indium doped tin oxide films. Transparent electrodes are widely used in optoelectronic devices such as displays, organic light emitting diodes, smart windows, solar cells, and touch screens. The performance of a transparent electrode is generally determined by the trade-off relationship of sheet resistance (Rsh) and optical transmittance (T), but other properties also affect the validity of the material as a transparent electrode. A method of removing the junction resistance without compromising the optical transmittance has become a key issue in the improvement performance. Here, we combine electrospinning and low Ar ion bombardment to fabricate metal nanopattern. In this study, metal films are patterned into transparent metal networks by using electrospinning fibers as a mask. By selectively removing the polymer layer used as a mask, a three-dimensional nanostructure was made easier. It is thought to be applicable to sensors and various fields in the future by increasing the surface to volume ratio. After removal of the prepatterned nanofiber, high aspect ratios and high-resolution patterns of target metals are created. After removing the nanofibers used in the patterning, a pattern of a target metal having a high aspect ratio and a high resolution was obtained. This method eliminates organic contamination and junction resistance, which is an issue of the solution process, by using a vacuum process and provides high performance transparency. The electrode can be manufactured without other high-cost patterning methods. The transparent electrode (T550 nm = 90 %, Rsh = 6 Ω / □) fabricated in this study is similar to a commercial ITO (T550 nm > 90%, Rsh = 10 Ω / □) that can replace ITO.