Based On Silicon Nanoporous Pillar Array Of Thin Films Of Tungsten Trioxide Gas Humidity Sensing Performance

With the rapid development of information technology and improvement of standard of living, people care more about of the living environment, so much high level sensors used in detecting environment are required.Semiconductor ceramics material tungsten oxide (WO₃) has the advantages of good heat stability and long service life, so it has an extremely wide application prospect. Silicon nano-porous pillar arrays (Si-NPA) has a special morphology of micron/nanometer structural composite system. With the advantages of large surface areas, very effective pathway for gas and easy compatible with the Silicon Microelectronic Technology, Si-NPA could be the excellent template for sensors.Here, WO₃/Si-NPA composite films sensor could be obtained by depositing the tungsten oxide nano-crystal on Si-NPA through spin-coating method. We has done some experiments for this work and the results as below:First, WO₃ collosol, which showed good stability, has been prepared by oxidation tungsten powder with hydrogen peroxide. By Spin-coating technology, the single particle layer and Crack-free WO₃/Si-NPA composite films was obtained, and the pillar-like structure characteristics of Si-NPA were kept well.Second, the WO₃/Si-NPA humidity-sensitive element's response to humidity were measured in a serious different humid ambient. Investigated the influence of frequency on the characteristic of capacitive-humidity and sensitivity-humidity response, we find the best test frequence is 100Hz. WO₃/Si-NPA sensor has the advantage of high sensitivity, strong output signal intensity, good linearity, long-term stability. WO₃/Si-NPA sensor's response to water was donated by the WO3 and the Si-NPA together.Third to meet the requirement of experiment, we design and implement a test system for gas-sensors; This test system can control of gas flow velocity, humidity and so on. The WO₃/Si-NPA sensor shows good sensitivity to NO₂ in certain humidity conditions at room temperature.