For high sensitivity in micro bio-analysis devices (MBD), the fabrication of the micro-structured reaction field using vertically aligned carbon nanotubes (VACNTs) which is pillar-structured by two methods was performed. The first method is the combination of photolithography and thermal chemical vapor deposition (CVD). The second method is the molding process of polydimethylsiloxane (PDMS) substrate with micro-pillars array and the transfer press of VACNTs synthesized by thermal CVD on PDMS substrate for lower cost in mass production compared with photolithography process. In the first method, circular-pattered metal film on silicon (Si) substrate as the catalyst for VACNTs synthesis was fabricated by photolithography and VACNTs-pillars array was successfully fabricated using the substrate with circular-pattered metal film by thermal CVD. Furthermore, the protein adsorption property of these structures was evaluated as the reaction field of MBD by ultraviolet (UV) spectroscopy. The results show that the protein adsorption property was improved considering the design of micro pattern in VACNTs structures. On the other hand, in the second method, pillar-structured PDMS substrate was molded using a photoresist mold by photolithography and VACNTs was transferred on PDMS substrate by transfer-press equipment. The results indicate that VACNTs can be transferred on the top of micro pillar of PDMS substrate controlling the load of transfer press. Furthermore, it is indicated that micro-pillar VACNTs structures can be fabricated by molding and transfer press with lower cost than the combination of photolithography and thermal CVD.
Vertically aligned carbon nanotubes (VACNTs or CNTs) were synthetized by thermal chemical vapor deposition method on the Si/SiO2 substrates, using Al/Fe as catalyst. In the present study, the influence of the annealing duration and synthesis time on the length, grow rate and quality of the VACNTs according to 9 different regimes was investigated. The outcomes of the study was observed using scanning electron microscope, atomic force microscopy and Raman spectroscopy analysis was utilized in order to evaluate the quality of the obtained nanotubes. Results have shown that the length of the VACNTs increases with the rise of annealing time, however only to a certain degree, after which the deterioration of the nanotubes occurs and the reduction of their length is noticeable.
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