カーボンナノチューブシートを用いた水素センサーの開発

Abstract

Due to their high specific surface area and measurable change in conductance according to the chemical environment changes, carbon nanotubes (CNTs) have been proved to be an ideal material for next generation of gas sensor. However, before CNTs-based sensor can become a candidate for commercial implementation, there are still challenges including mass production of sensor arrays and improvement of sensor reproducibility. In this research, a high sensitivity CNT sheet-based gas sensor was fabricated, which can push forward the commercialization of CNT-based sensor. By controlling the reaction conditions during chemical vapor deposition (CVD) process, a spinnable CNT array was synthesized reproducibly. The CNT sheets were drawn from a sidewall of spinnable CNT array. CNT sheets were directly fixed onto Au electrodes and were heated up to 300°C for 2 h to oxidize amorphous carbon. Gas detection toward hydrogen gas was operated in a quartz tube chamber. With the change of gas concentration, the change in sensor resistances as response and recovery behavior was measured using a programmable electrometer. A sensitivity of 5% for 4% H2 was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H2 gas at room temperature was achieved by Pd functionalization.