The Research Of Synthesis Of Nanocrystalline TiO₂ And Ag₂O Thin Films Based On SAMs Technology

Nano-material is a new functional material, and is widely used in many fields such as photocatalysis, solar cell, gas sensor, package, coating and so on. By using the self-assembly technique and the liquid deposition technique, the nanocrystalline oxide thin films were deposited on sulfonated self-assembled organic layers on the substrates at low temperature respectively. The as-deposition films on the SAMs were uniform, dense, with excellent adherence and controlled thickness, the technology will become a potential aspect in the field of functional material.The nanocrystalline oxide titanium thin films were deposited on sulfonated self-assembled organic layers on the silicon and glass substrates at 50oC respectively. The structure, phase composition of the deposited tin oxide films was determined via XRD. The results indicated that uniform TiO₂ thin films with densely packed were anatase and rutile crystallites .And the as-depositon TiO₂ thin films with well hydrophile performance and transmittance in visible light wavelenth.The nucleation free energy of precursor solution was investigated by using the classical crystal nucleation theory. The results indicated the organic SAMs , which promoted the heterogeneous nucleation and deposition of the precursor solution onto the substrate surface, had been confirmed an effective inducement for the crystal and growth of the oxide films. The herterogeneous free energy of the TiO₂ and SnO2 thin films were 15mJ/m2,62mJ/m2 respectively. With compared the results showing that the functional film's induce effect for SnO2 herterogeneous nucleation was stronger than for TiO₂ heterogeneous nucleation. And the SnO2 thin film's growth rate were better than TiO₂'s.The marriage of SAMs with Liquid Phase Deposition creates a new method to prepare semiconductor materials. The results was characterized by means of AFM , SEM and the test of resistance-temperature. These SAMs-oriented Ag2O thin films showed well-set and a preferable resistance-temperature relation, which indicated that these Ag2O thin films were promising materials for application as gas sensors to detect poison-gases.