The Research And Performance Test Of Chemical Sensors Based High-Density Aligned Arrays Of Carbon Nanotubes

The aligned single-walled carbon nanotubes arrays were synthesized on quartz substrate by chemical vapor deposition(CVD), using copper as catalyst and methane as carbon source. The sample's structure was characterized by scanning electron microscope, atom force microscope. We investigated several factors influencing the growth of aligned carbon nanotubes arrays, such as the annealing time and temperature, Poly(methyl methacrylate)(PMMA) added to catalyst solution in order to disperse catalyst, stripe catalyst to improve alignment and density. The aligned single-walled carbon nanotubes arrays were transfered onto the SiO₂/Si substrate by PMMA. We made devices through microfabrication on quartz and silicon substrates and performed electrical measurement using semiconductor parameter test system.The alignment could be improved through optimize annealing conditions. It was found that the best annealing temperature and time was 860 degrees and 8 hours, respectively. The activity of catalyst and the density of carbon nanotubes were enhanced by using PMMA. In addition, the alignment could be improved by patternning the catalyst into arrays of stripes. The optimized density of carbon nanotubes can be 3 SWCNTs/um. We performed electrical measurement on the Field Effect Devices made with these nanotubes, which shows p-channel characteristics. It was proved that the device mobility was affected remarkably by channel length, and the mobility for 5μm channel length device was higher than that of 3μm channel device.