Resistive humidity sensitivity of arrayed multi-wall carbon nanotube nests grown on arrayed nanoporous silicon pillars

Arrayed multi-wall carbon nanotube (CNT) nests were grown on a silicon nanoporous pillar array (Si-NPA) by thermal chemical vapor deposition and the corresponding microstructure was characterized. The room-temperature resistive humidity sensing properties and the electrical conducting mechanism of the CNT/Si-NPA were studied by a standard four-probe method and a hot probe method, respectively. It was shown that with the relative humidity (RH) changing from 11 to 85%, a resistance device response over 362% was achieved, and the curve of the resistance response with RH is of high linearity. The high device repeatability was demonstrated by carrying out vapor adsorption–desorption dynamic cycles, and the response and recovery time were determined to be 64 and 51 min, respectively. These sensing performances given by CNT/Si-NPA are attributed to the unique surface structure, morphology and chemical inertness of the CNT/Si-NPA.