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Preparation and Characterization of ZnO Films Coated on the Glass Substrates by Spray Pyrolysis Method

Author: ZuoDengKui
Tutor: ZhaoQingNan
School: Wuhan University of Technology
Course: Materials Science
Keywords: ZnO films Optical Performance Annealing Transparent conductive Spray pyrolysis method
CLC: TB383.2
Type: Master's thesis
Year: 2010
Downloads: 53
Quote: 1
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Abstract

ZnO is a wide bandgap semiconductor material, the band gap of 3.37eV. ZnO transparent conductive film is a n-type semiconductor, this is because during the preparation of the film, Zn and O with stoichiometric ratio does not meet, but rather the formation of a state of hypoxia. ZnO can be adjusted over a wide range and control films produced under different conditions with different functions. Incorporation of the ZnO film of aluminum, indium, fluorine and other impurities, can effectively improve the conductivity of the film, to improve its performance. Doped ZnO films have good electrical conductivity and transparency, which AZO film optoelectronic devices have become an ideal material for preparation is one of the hot research in recent years. This zinc acetate as a precursor to, AlCl3, InCl3 of dopants, the glass substrate was prepared by spray pyrolysis doped ZnO transparent conductive thin film. Doping elements determined by experiments, doping concentration, substrate temperature, initial concentration of zinc acetate solution, spray distance and other factors and the substrate of ZnO thin films, to find the best process parameters. Preparation of solar cell manufacturing process to meet the requirements of a ZnO-based transparent conductive films. Continuous improvement in the test Spray pyrolysis equipment, industrial production is met ZnO-based thin film production equipment. UV - visible spectroscopy (UV-Vis) tested the film transmittance and absorption rates, the optical constants of the film: the refractive index of the optical band gap and the film thickness; with a high power microscope the surface morphology of the films ; studied the spraying process on the film surface morphology; tested with four probe method sheet resistance; using XRD crystal structure of the films. The results showed that: (a) a substrate temperature which affect the film structure and properties of the important factors, the use of spray pyrolysis method at 550 ℃, when the In doping amount of 1%, the prepared films reached a minimum resistivity of 3.5 × 10-3Ωm, in the visible region (400-800 nm) in the transmittance of about 80%, the optical band gap of 3.24eV doped ZnO film; (2) were prepared by spray thermal decomposition of a ZnO thin films polycrystalline hexagonal wurtzite structure of thin films along the (002) plane of preferential growth, the increase with In-doped film composed of hexagonal crystal structure of hexagonal system obliquely change. But the (002) diffraction peak strongest, most acute. When the In-doped greater than 1%, the film appears the new structure InAlO3 (ZnO) 17 structure appears; (3) prepared by spray pyrolysis of In-doped ZnO films minimum resistivity of 8.0 × 10-5Ωm than Al-doped miscellaneous minimum resistivity of ZnO thin films 3.5 × 10-3Ωm low of two orders of magnitude; while the transmittance of ZnO thin films doped trace, without the impact of doping elements. Therefore, the thermal decomposition process of the spray element ratio of In in Al as a doping element is more suitable for preparing high ZnO films.

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