Tunable growth of single‑wall CNTs by monitoring temperature increasing rate

We report here new aspects of CNT growth by CVD system where temperature increasing rate plays a key role in controlling the diameter, structural quality, and yield of CNTs. Temperature increasing rates were used in the range 100–600 °C/h and growth morphology was constantly monitored at every step by HRTEM, FESEM and Raman spectroscopy. Morphology as well as structural quality of CNTs is sharply enhanced with the increase in temperature increasing rate, and it is found that the onset of SWNTs growth starts at 600 °C/h. In this work, we also proposed that the diameter of grown CNTs is independent from the size of catalyst particles used for initiation of CNTs growth unlike the conventional concept in the feld of CNTs growth.