No ₂ Study On Preparation And Characteristics Of Thin Film Of Gas Sensor Array

With the development of the microelectronic and self-assembled films, chemical sensors prepared by ultra thin film technology have been drawn more and more attention in recent years. The dissertation focus on the design and preparation of device structure for NO₂ gas sensor array, the fabrication and structural characterization of self-assembled PAN composite films with polymeric acids, the gas-sensing properties and gas-sensing mechanism. The main results are as follows: 1. Based on the conventional MOSFET, a new kind of novel chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated for the first time. The sensor is a device with self-assembled PAN composite films with polymeric acids deposited on the gate area of MOSFET replacing the gate metal. 2. Gold colloids with different particle sizes were synthesized using hydrogen tetrachloroaurate as the precursor and NaBH₄ and/or Na₃-citrate as the reducing agents. Gold nanoparticulate thin films were built up using the electrostatic self-assembly technique and Self-assembled polyaniline (PANI) composite films with poly (styrenesulfonic acid) were fabricated based on doping-induced deposition effect above the aurum. These films and the fabrication processing were characterized by Quartz Crystal Microbalance (QCM), UV-Vis absorption spectrum (UV-Vis), atomic force microscopy (AFM), infrared reflect-absorbance (RA) spectra, X-ray photoelectron spectroscopy (XPS) and the colloids was characterized by X-ray Diffraction (XRD) and UV-Vis, too. The gas-sensing property of the film has been studied in detail. The experimental results show that: (1) The gold colloid was a monodisperse suspension and has more uniformity micro-particle with more sodium citrate or NaBH4.The colloid synthesized using NaBH₄ with ethanol has the most excellent property for self-assemble and has a micro-particle diameter of 1.7 nm. (2) The self-assembled PAN films above the aurum were uniform and solid, and have good adhesion to substrates. And there has new infrared...