| Transflective film is one of the most important opto-electric materials in liquid crystal display. A new type of transflective technology will be indispensable in modern liquid crystal display. Cu/ITO/Ag multilayer films, composed of highly reflective and conductive metal Ag and Cu and transparent conductive materials of ITO, could be prepared with excellent performance for new transflective technology. So the research of Cu/ITO/Ag multilayer films will have important significance and practical value.Cu films with different thickness5.4,10.7and16.1nm and Ag film with lOnm which were measured by surface profiler, were deposited on glass substrates by DC magnetron sputtering at room temperature. The crystallographic properties of Cu films and Ag film were characterized by XRD. The surface morphology of Cu films and Ag film were studied by SEM and3D Profilometer. The surface roughness of Cu films and Ag film were calculation from3D profilometer. The optical properties of Cu films and Ag film were measured by ultraviolet-visible spectrophotometer. The electrical conductivity of Cu films and Ag film were evaluated by a four-probe meter which can carry out dual electrical measurement.Cu/ITO films were prepared on the basic of Cu layer by RF magnetron sputtering at room temperature. The thickness of ITO film is about144nm measured by surface profiler including surface roughness. The micro structure, surface morphology, surface roughness, optical properties and electrical properties of the films were characterized by X-ray diffractometer, scanning electron microscope,3D profilometer, ultraviolet-visible spectrophotometer, four-probe meter, respectively. The influence of Cu thickness on the microstructure, surface morphology, optical properties and electrical properties of Cu/ITO films were studied.Ag layer was prepared on the basic of ITO and Cu/ITO films by DC magnetron sputtering. The microstructure, surface morphology, surface roughness, optical properties and electrical properties of ITO/Ag and Cu/ITO/Ag films were also characterized by X-ray diffractometer, scanning electron microscope,3D profilometer, ultraviolet-visible spectrophotometer, four-probe meter, respectively. The influence of Cu thickness on the microstructure, surface morphology, optical properties and electrical properties of the Cu/ITO/Ag films were studied.Finally, Ag/ITO/Cu films were prepared use the same method. The optical properties of Cu/ITO/Ag and Ag/ITO/Cu films were compared at last. Efficiency factor and light splitting ratio were established for evaluating photoelectrical properties of Cu/ITO/Ag films.The results show that Cu films are amorphous. Ag (111) diffraction peak can been found from XRD patterns. The surface roughness of Cu films increases with increasing Cu thickness. Because Cu film and Ag film are discontinuous, the surface roughness of the Cu film and Ag film is close to the film thickness, it is in conformity with the results of SEM. The optical properties of Cu/ITO and Cu/ITO/Ag films are influenced by bottom-layer Cu film thickness. With increasing the thickness of Cu layer, the transmittance drops and the absorption coefficient increases. The reflectance presents oscillation. It reaches maximum for the16.1nm thickness Cu layer. The transmission of triple layer film is lower than double layer film, while the reflectance and absorption coefficient are higher, because of the increasing of total thickness and the high reflection and high absorption of Ag. The transmittance of Ag/ITO/Cu films increases more significantly than Cu/ITO/Ag films, whereas the reflectance and the absorption coefficient of Ag/ITO/Cu films are approximate to the Cu/ITO/Ag films. The main reason is the difference of the surface. It is indicated that when the Ag film is close to the external light, it can make good use of back light.The main innovations of the investigation are as follows:1. The structure and properties of Cu, Ag and Cu/ITO films are studied, respectively.2. Cu/ITO/Ag and Ag/ITO/Cu multilayer films have been prepared by DC and RF magnetron sputtering. The photoelectrical properties of Cu/ITO/Ag film are analyzed from the structure and surface roughness of Cu layer. The optical properties of Cu/ITO/Ag and Ag/ITO/Cu films are compared. 3. Efficiency factor and light splitting ratio are established for evaluating photoelectrical properties of Cu/ITO/Ag films. The Cu/ITO/Ag films with excellent optical and electric properties portend its potential application in future new-type transflective displays. |
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