The present paper describes the effect of co-catalyst on the growth of multiwall carbon nanotube (MWCNT) by chemical vapor deposition (CVD) technique. The fascinating properties of CNT make them a suitable material for optoelectronic devices such as sensors, LED, solar cell, and field emission displays. MWCNTs were fabricated using CVD, by decomposing ethanol over finely dispersed Co metal as a catalyst at 750 °C. The effects of growth condition on the quality and morphology of MWCNTs were investigated by SEM, FTIR and XRD. SEM photographs show that the nanotubes are densely packed having a diameter of 10–15 nm. The bandgap was calculated by UV–visible spectroscopy and it was found varying from 3.08 to 3.5 eV by changing the substrates. The average size of tubes (length) was found to be 250 nm. FTIR exhibited that the synthesized MWCNTs were semiconducting in nature with the oxygen vacancies causing the variations in refractive index with the exposure of moisture.

中文翻译：

---

CVD催化生长MWCNT及其在光电湿度传感器中的应用

本文通过化学气相沉积（CVD）技术描述了助催化剂对多壁碳纳米管（MWCNT）生长的影响。CNT的迷人特性使其成为光电器件（如传感器，LED，太阳能电池和场发射显示器）的合适材料。使用CVD通过在750°C的细分散的Co金属作为催化剂上分解乙醇来制造MWCNT。通过SEM，FTIR和XRD研究了生长条件对多壁碳纳米管质量和形貌的影响。扫描电镜照片显示纳米管被密集堆积，直径为10–15 nm。带隙是通过紫外可见光谱法计算得出的，发现通过改变底物，带隙在3.08至3.5 eV之间变化。发现管的平均尺寸（长度）为250 nm。