Effects of thickness of Ni layer deposited on glass substrate on the growth and emission properties of carbon nanotubes

Vertically aligned carbon nanotubes were grown on the Cr-coated glass substrate with different thickness of Ni catalyst layer at low temperatures (<600 °C) using plasma-enhanced hot filament chemical vapor deposition (PEHFCVD). The diameter of carbon nanotubes grown for 14 min increased from 32 to 113 nm as the thickness of Ni layer increased form 10 to 100 nm. However, the diameter of carbon nanotubes grown for 34 min was almost same irrespective of Ni layer thickness. The emission characteristics of carbon nanotubes (CNTs) were dependent on the diameter of carbon nanotubes and substrate. Turn on electric field, Eto, increased from 6.9 to 9.6 V/μm as the diameter of carbon nanotubes increased from 44 to 64 nm. Eto of carbon nanotubes without Cr buffer layer was lower than that of carbon nanotubes with Cr layer. The electron emission from carbon nanotubes grown on Si substrate was larger than that of carbon nanotubes on glass substrate with the same Cr and Ni layer.