Electrical Properties Of Tin Oxide Composite Thin Films Fabricated By Sol-gel Method

Tin oxide is a kind of typical n-type metal oxide semiconductor material. Due to its excellent perfromance in conducitivity, optics and resisting, it has been widely applied in the fields of transparent conductive thin films, solar cell, gas sensors and so on. Domestic and foreign research progresses in SnO2thin films were reviewed in this paper. Sol-Gel method was adopted because of its advantages, such as low cost, easy deposition of thin film.In experiment, firstly, we using metal salts SnCl2·2H2O, CuCl2·2H2O and ethano as precursors, thin films of tin oxide and copper oxide-doped tin oxide with good electrical properties have been deposited by the sol-gel method. After that, some key parameters were defined by the X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscopy (TEM) and Electrochemical workstation, such as thin films microstucture, morphology, resistance and so on. It has been found that the optimum heat treatment temperature ia about450℃-500℃and higher temperature can benefit the crystallization of tin oxide crystals, the tin oxide crystals exist mainly as tetragonal rutile structure, despite of some rhombic SnO crystals. The resistance of copper oxide doped tin oxide is lower pure tin oxide in all heat treatment temperature. In view of the various factors, we choose the heat treatment temperature is450℃. In this temperature, we studied the electrical properties of copper oxide depod tin oxide with different number of spin coating layers and the different content of polythylene glycol (1000), this films were also analyzed by means of XRD, SEM, TEM and Electronchemical workstation.In theorly, with the combination of the aerodynamics and the theory of gas adsorption, we present a simple model for the simulation of the steady state gas sensitivity of a metal oxied thin film gas sensor. The model puts forward a general mathematical relationship between the steady state sensitivity of the gas sensor and the thickness of the sensitivity film used. Besides we propose another model which will be used for analyzing the response time depedence of metal oxide thin film thickness. In summary, we fabricated a series of tin oxide and copper oxide doped tin oxide thin film with different content of polythylene glycol (1000) with using sol-gel method, The film samples were systematically characterized aspects of microstrcture and electrical properties, In theory we present a simple model for the simulation of the steady state gas sensitivity of a metal oxied thin film gas sensors. Besides, we propose another model that can be used for analyzing the response time depedence on metal oxide thin film thickness.