One-step growth process of carbon nanofiber bundle-ended nanocone structure by microwave plasma chemical vapor deposition

In this work, we report a simple one-step growth process to synthesize a novel and distinct carbon nanostructure, called a carbon nanofiber bundle-ended nanocone (CNFNC) structure, by using microwave plasma chemical vapor deposition (MPCVD) method with CH4 and H2 as source gases and Fe catalyst. The nanostructures and their properties after each processing step were characterized by FESEM, HRTEM, ED, AES, and Raman spectroscopy. The preliminary results have demonstrated that the CNFNC structures exhibit excellent field emission properties. The results also show that the favored conditions to form the CNFNC structures include a combination of lower CH4/H2 flow ratio, higher substrate negative bias, and proper working pressure and deposition time. The possible growth mechanism of the CNFNC structures is proposed.