Growth and patterning of novel catalysts in microreactors utilizing carbon nanotubes as templates
Tay, Beng Kang
Date of Issue2008
School of Electrical and Electronic Engineering
Thin carbon films have been deposited by filtered cathode vacuum arc technique and a low bias voltage power supply. The substrate bias voltage ranged from -80 to -400V. It is important for thin films to have low internal stress and good adhesive properties for any applications. The results ascertain that stress levels were high at the bias voltage between -100 and -200V. By analyzing the relationship between the compressive stress and the negative bias voltage applied on substrates, certain trends can be observed. Stress levels fluctuate greatly between -100V and -170V and the peak stress level would occur in this range. Delamination is likely to take place on films will high level of stress. Carbon nanotubes (CNTs) were grown on Ni catalyst layer under-CNTmetallization layers, namely Si02, AI, Cu and Cr, using hot filament chemical vapour deposition (HFCVD). The morphology and microstructure of the CNT were analyzed by scanning electron microscopy (SEM) and Raman spectrometer. It was found that the level of interaction between the Ni catalyst layer and under-CNT-metallization layer has significant effects on carbon nanotubes growing characteristics. It was observed that carbon nanotubes grown on Si02 under-CNT-metallization layer recorded the highest density and smallest diameter. When Cu or Cr under-CNT-metallization layers were employed, high density and larger diameter nanotubes were obtained. No carbon nanotubes were found on samples with AI under-CNT-metallization layer under similar growth conditions.
DRNTU::Engineering::Electrical and electronic engineering::Nanoelectronics