A greenhouse gas silicon microchip sensor using a conducting composite with single walled carbon nanotubes

A new silicon substrate microsensor has been developed using a composite made of carbon nanotube and Baytron-P that senses the greenhouse gas carbon dioxide gas at 22 °C. The sensor was constructed with a Si chip by depositing the composite between two gold electrodes. Two identical Si chips were connected in a parallel configuration to reduce the initial resistance of the sensor. The resistance of the sensor decreases upon exposure to the greenhouse gas that is proportional to the concentration of carbon dioxide. The sensor showed a semiconducting behavior with a negative temperature coefficient. The response time of the sensor is about 40 s. The Fourier transform infrared spectroscopy showed peaks for the nanocomposite at 1056 cm−1, 1195 cm−1, 1296 cm−1, 1635 cm−1, 2083 cm−1, 2345 cm−1 and 3278 cm−1. The carbon dioxide adsorption on the composite results in the polystyrene sulfonate absorption band shifting from 1195 cm−1 to 1176 cm−1 suggesting a phase separation occurring in the nanocomposite that result in the increased conductivity.