A simple method to fabricate chemical sensors using horizontally aligned clean carbon nanotubes

We have developed a simple and inexpensive method to fabricate carbon nanotube-based chemical sensors by fabricating a horizontally aligned carbon nanotube film on a titanium/gold-coated glass plate using electrophoresis and fissure formation techniques. The sensors exhibited low noise and thus high sensitivity to the NH3 and NO2 molecules and the response times were relatively short. They were completely recovered within 40 s when a dc voltage of 5 V was applied for less than 30 s. The fabrication processes do not require any expensive equipment like e-beam lithographs. They are relatively simple and low-cost, and the sensors themselves are mass-producible.