플라즈마 화학기상증착 장비를 이용한 탄소나노튜브 3차원 네트워크 구조체 제작에 관한 연구

Abstract

Carbon nanotubes (CNTs) have attracted much attention because of their excellent electrical and mechanical properties. Especially, it is expected that a high density CNTs array is useful for many applications such as highly sensitive electrical detectors, optical absorbers and biosensors. In order to increase the density of CNTs array, many research groups focused on the fabrication of high density CNT network structures on the three-dimensionally patterned substrate using synthesis and manipulation methods. In case of manipulation method, allocating of CNTs on the three-dimensional (3D) structure is very difficult. So, several research groups developed the synthesis method of CNTs on the 3D structure using thermal chemical vapor deposition (CVD) and plasma enhanced CVD (PECVD). In case of PECVD, hydrocarbon gas was dissociated by plasma at lower temperature. Thus, the PECVD is possible to synthesize CNTs at low temperature compared with thermal CVD process. However, the synthesis of CNTs using PECVD have many structural defects and bent structures compared to those prepared by the thermal CVD process due to a etching effect of the plasma ions. These defects have a bad influence on the formation of CNT interconnection in 3D structure. In order to fabricate 3D network structured CNTs by PECVD, it is necessary to reduce the plasma etching effect. The plasma etching effects is dependent on the ion kinetic energy. In this study, a metal mesh was installed between plasma apparatus and substrate to reduce the ion kinetic energy. In case of using the metal mesh, ions can freely diffuse through the holes with decreased kinetic energy. When the plasma treated on the single-walled CNTs (SWCNT) network, most SWCNTs were etched by plasma without a mesh. On the contrary, most SWCNTs networks remained after plasma treatment with mesh. This difference in the SWCNT etching between with and without a mesh is attributing to the fact that mesh successfully reduced plasma etching effect by lowering kinetic energy of ions. Therefore, the 3D network of SWCNTs can be successfully fabricated by using the mesh against plasma etching effects.