tailieunhanh - Features of Liquid Crystal Display Materials and Processes Part 3

Tham khảo tài liệu 'features of liquid crystal display materials and processes part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Transparent ZnO Electrode for Liquid Crystal Displays 29 Resistance of transparent conductive ZnO film The resistivity of the film is one of the most important characteristics required for application of alternative transparent electrodes to ITO used in LCDs. The resistivity of ITO transparent films is in the range of pQm Wakeham et al. 2009 Shin et al. 1999 . Therefore transparent conductive ZnO films as an alternative must have a resistivity of less than ca. pQm. In the case of thin films the resistivity is generally derived from the carrier-flow in the plane of the films. The resistivities of even metal films increase with the decrease in film thickness especially less than ca. 100 nm. Such a phenomenon is caused by the increase in the frequency of collisions or scattering with the carrier-flow and the film surface the interface with the substrate and irregular crystalline structures in the region of the substrate. The resistivity of the GZO film also shows a similar dependency on the film thickness as shown in Fig. 5 a . Fig. 5. Electrical characteristics of GZO film as a function of the film thickness. As the film thickness decreases the carrier mobility and concentration in the film decreases as shown in Figs. 5 b and c . The data in Fig. 5 was obtained from GZO films prepared using RPD at 180 C. The electrical characteristics of transparent conductive ZnO films formed by the magnetron sputtering showed similar dependencies on the film thickness although the values were significantly affected by the formation conditions . type of dopant and its concentration the deposition equipment temperature pressure and the electrical power supplied to the source during deposition. Figure 6 shows a comparison of the resistivities of GZO and AZO films formed with an Ar sputtering pressure of Pa at room temperature or at 180 C using the conventional planar magnetron sputtering system. The ZnO sputtering target materials for the deposition of GZO or .