Light-poweredcarbon nanotube-silicon nanowire heterojunction gas sensors

摘要

Carbon nanotubes (CNTs), with large surface area, high charge mobilityand excellent thermal stability, have been considered as candidates forgas sensor materials. However, assembling and testing of single carbon nanotube gas sensors are very complex and expensive processes. Moreover, in order to obtain high sensitivity, traditional CNT gas sensors are generally heated to a high temperature, which is also increasing an additional risk for combustible gas detection. In our previous works, we directly configured carbon nanotube films onto silicon (Si) wafer to form heteroj unction solar cells. In this model,carbon nanotubes served as energy conversion materials, a charge carriers collecting/transport layer and transparent electrode. Due to large surface area of CNTs, the physical and electronic properties of CNT filmswereeasily modified by chemical treatments.As a result, the solar cells were exquisitely sensitive to the chemical environment surrounding and could be used as gas sensors. Furthermore, CNTs-Si heteroj unction gas sensors could work at room temperature and only use light as energy source.