Effect of TiO 2 Addition on the Secondary Electron Emission and Discharge Properties of MgO Protective Layer
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Effect of TiO2 Addition on the Secondary Electron Emission and Discharge Properties of MgO Protective Layer Younghyun Kim, Rakhwan Kim, Hee Jae Kim1, Hyeongtag Jeon and Jong-Wan Park Dept. of Metallurgical Engineering, Hanyang University, Seoul 133-791, Korea 1 Dept. of Ordnance Engineering, Korea Military Academy, Seoul, KOREA ABSTRACT Secondary electron emission from a cathode material in AC PDP (Plasma Display Panel) is dominated by potential emission mechanism, which is sensitive to band structure of a protective layer. Therefore, the secondary electron emission property can be modified by a change in the energy band structure of the protective layer. Mg2-2xTixO2 films were prepared by e-beam evaporation method to be used as possible substitutes for the conventional MgO protective layer. The oxygen content in the films and in turn, the ratio of metal to oxygen gradually increased with the increasing TiO2 content in the starting materials. The pure MgO films exhibited the crystallinity with strong (111) orientation. The Mg2-2xTixO2 films, however, had the crystallinity with (311) preferred orientation. The stress relaxation, when the [TiO2/(MgO+TiO2)] ratio in the evaporation starting materials was 0.15, seems to be related to inhomogeneous film surface due to an excessive addition of TiO2 to MgO. When the [TiO2/(MgO+TiO2)] ratios of 0.1 and 0.15 were used, the deposited films exhibited the secondary electron emission yields improved by 50% compared to that of the conventional MgO protective layer, which resulted in reduction in discharge voltage by 12%. INTRODUCTION The AC plasma display panel (AC PDP) has recently received much attention in research and development as an alternative to the cathode ray tube (CRT). The AC PDP is also considered as a promising wall hanging TV set because there have been growing demands for the largesized TV screens which are thin and light. The current MgO protective layer for the promising wall hanging TV, AC plasma display panel is thought to be still not one of the best materials to meet the demand of advanced high vision PDP with good light emission efficiency, low power consumption, low production cost and high image fidelity [1]. Therefore, to improve the overall performance of PDP, it is indispensable to develop new protective materials that can reduce the required voltage for discharging, and which will then be compatible with integrated circuits [2]. If other variables such as gas composition, electrode gap, electrode width and barrier height are constant, the operation voltage of ACPDP is closely related to secondary electron emission from protective layer for dielectric layer [3]. The secondary electron emission property of the protective layer is affected by its energy band structure such as electron affinity, work function, bandgap energy and intraband level [4]. In this study, Mg2-2xTixO2 protective layers evaporated from the starting materials with different [TiO2/(MgO+TiO2)] ratios were introduced, and then the effects of TiO2 addition on physical and electrical cha
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