The Ethanol Sensing Properties Of In₂O₃ Nanoparticle Grown On Silicon Nanoporous Pillar Array

Since the 1990 s, the gas sensing properties of a new sensitive material of In₂O₃ got the extensive research both at home and abroad. Nanotechnology has been greatly used in medical treatment, health, industry, agriculture, military, aerospace and other fields after nearly half a century rapid development. Similarly, the application of nanotechnology in sensors is vital for the development of sensor, using different preparation methods for various morphology structures with large specific surface area is one of the main development directions of gas sensors. In₂O₃ has great research potential in gas sensor and the advantages of high sensitivity, fast response and recovery.In this paper, we prepared a nanometer In₂O₃ thin film on the silicon nanoporous pillar array（Si-NPA） by the chemical vapor deposition （CVD） method and the vacuum vapor deposition technology, obtained the In₂O₃/Si-NPA composite system. The morphology structure of In₂O₃/Si-NPA composite system had been controlled by changing the preparation conditions. The composition and morphology of In₂O₃/Si-NPA composite system prepared with the two methods were characterized and analyzed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. The resistance type gas sensors were prepared through thermally evaporating coplanar interdigital aluminum electrodes onto In₂O₃/Si-NPA. The gas sensing performance of gas sensor based on the In₂O₃/Si-NPA was studied with the change of surface morphology structure.The results show that the nanometer In₂O₃ prepared by CVD method and vacuum evaporation technology with different growth and deposition time has good sensing performance for ethanol, respectively. But, morphology structure and specific surface area make the sensing performance of the gas sensor have large changes. When In₂O₃ film prepared by two methods is thin, the In₂O₃/Si-NPA gas sensor has low response, long response and recovery time for ethanol; when In₂O₃ film prepared by two methods is thick, the In₂O₃/Si-NPA gas sensor has high response, short response and recovery time for ethanol. The In₂O₃/Si-NPA gas sensor prepared with two methods has high ethanol sensing properties. The high sensing performance is attributed to the large specific surface area and more surface active sites of In₂O₃/Si-NPA composite system.