Nishant Tripathi

Effect of Growth Temperature on the Diameter Distribution and Yield of Carbon Nanotubes

Growth of carbon nanotubes (CNTs) on iron sputtered Si substrate has been done by using self design Thermal Chemical Vapor Deposition (TCVD) at atmospheric pressure. Parameters of CNTs are highly dependent on the growth temperature. A strong relation between CNT’s diameter, yield and growth temperature was found. The experiments were done in the temperature range of 750–900 °C with an interval of 25 °C. It was found that at 750 °C there was no growth of CNT. However, at 775 °C, the horizontal network of CNTs having diameter range of 8–12 nm with sufficient yield was observed. As we increase the temperature, an increase in CNT’s diameter and decrease in yield was found. These results demonstrate that diameter and yields of CNTs can be controlled with the growth temperature.

Growth of SWNTs using Cu(NO3)2 and CuO a systematic study on role of oxygen in growth of CNTs

We report an another unconventional growth of dense network Single Wall Carbon Nanotube (SCNTs) and Highly aligned Carbon Nanotubes using Cu(NO3)2 and CuO as catalyst. A systematic study for effects of oxygen on catalytic quality of Copper and on CNTs growth also studied. All reactions are performed in atmospheric pressure in thermal CVD chamber. The CNTs are characterized using HRSEM and micro-Raman. The ID/IG ratio and RBM peaks in raman spectra shows that grown CNTs are less defective SWNTs.

Sensitive detection of Nitrogen Dioxide using gold nanoparticles decorated Single Walled Carbon Nanotubes

The modification of carbon nanotubes (CNTs) could enhance their surface and electric properties. To this purpose, we explore the impact of a thin layer of gold (Au) on the surface of single wall carbon nanotubes (SWCNTs). SWCNTs have been grown by Chemical Vapor Deposition (CVD) method and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Surface morphology and microstructure of Au-SWCNT have been characterized by FE-SEM and Raman Spectroscopy. Using the present collective approaches, the improvement in the detection of NO2 gas using Au-modified nanotubes is explained. However, Au-modified SWCNT gas sensors exhibited better performances compared to pristine SWCNTs. These changes in resistance and the shift of the Fermi level just after NO2 exposure was probably due to adsorption of NO2 molecules on the surface of Au-SWCNTs. Surface modification of nanotubes with understanding of sensing ability at atomic level opens the new way to design a selectivity gas sensor.