| AVS 55th International Symposium & Exhibition | |
| Graphene Topical Conference | Monday Sessions |
| Session GR+TF+NC-MoM |
| Session: | Graphene and 2-D Carbon Nanostructures |
| Presenter: | W. Takeuchi, Nagoya University, Japan |
| Authors: | W. Takeuchi, Nagoya University, Japan M. Hiramatsu, Meji University, Japan Y. Tokuda, Aichi Institute of Technology, Japan H. Kano, NU Eco-Engineering Co., Ltd., Japan M. Hori, Nagoya University, Japan |
| Correspondent: | Click to Email |
Carbon nanowalls (CNWs), that is two-dimensional carbon nanostructure of freestanding vertically oriented graphitic sheets, attract great attentions because of several applications such as electrical devices. Recently, it was reported that the 2-D multilayer graphene sheet devices offer the high mobility and the huge sustainable currents. Therefore, CNW films would have high performances of electric devices, since the CNWs basically consist of graphene sheets. In order to realize the CNW devices, it is necessary to control structures and properties. In this study, we have successfully controlled structures and electric properties of CNWs. CNWs were fabricated on the quartz substrate by plasma enhanced CVD (PECVD) employing C2F6 gas with H radical injection. The influences of N2 and N2/O2 addition to C2F6/H2 gas mixtures on structures and electric properties of CNWs were investigated. The cross-sectional scanning electron microscopy (SEM), Hall measurement and secondary ion mass spectrometry (SIMS) were used to evaluate structures, electric properties and atomic compositions of CNWs, respectively. The SEM image of the CNWs film synthesizes by N2/O2 mixture gas addition indicated that the size of the individual graphene of CNWs increased with less branching. The Hall coefficient indicated the positive value for the CNW film synthesized without N2 addition. In the case of N2 addition, it displayed the negative one. The positive or negative value means p- or n-type conduction, respectively. CNW films doped with N atoms were characterized by SIMS to investigate the effect of the N2 addition on the atomic composition of CNWs. The carrier and N concentration in the CNW films formed by N2/O2 mixture gas addition were almost the same as those in the CNW film by N2 addition. It is considered that the N atom in the CNWs act as a donor and the electrical property of N-doped CNWs can be controlled by N atom concentration. These results will be crucial to fabricate the electrical devices of CNWs without deteriorating crystallinity.