Highly sensitive gas sensors on low-cost nanostructured polymer substrates

Abstract

SnO 2 thin-film gas sensors have been successfully fabricated on nanospiked polyurethane polymer surfaces, which are replicated by a low-cost soft nanolithography method from silicon nanospike structures formed with femtosecond laser irradiations. Measurements revealed significant response to carbon monoxide (CO) gas at room temperature, which is considerably different from the sensors of SnO 2 thin films coated on smooth surfaces that show no response to CO gas at room temperature. The high area/volume ratio and sharp structures of the nanospikes enhance the sensitivity of SnO 2 at room temperature. This will greatly decrease the electrical power consumption of the gas sensor and the cost for calibrations, and has great potential for application in other sensing systems.

The electric field effect on the sensitivity of tin oxide gas sensors on nanostructured substrates at low temperature

“…When the temperature exceeds 100°C, the sensor works again although the responses to the gases are very different from those at temperatures below 100°C. The sensing mechanism above 100°C is the same as that in previous work by others on hightemperature sensors [1][2][3][4][5][6][7][8][9][10][11], except for that the sensitivity of our sensor is much higher (33% versus 19% obtained with conventional sensors which measure CO gas of 12 ppm [15]) because of the surface area enhancements and the long-range Coulomb interaction [16]. The results in Figure 3 suggest a different sensing mechanism as shown in Figure 4 at room temperature.…”