热处理对ZnO∶Zn荧光薄膜结晶性能的影响

Crystal Property of ZnO ∶Zn Thin Film Improved by Post-deposition Heat Treatment

用热处理方法对电子束蒸发制备的ZnO∶Zn荧光薄膜分别进行400,600℃退火处理。采用X射线衍射、X射线光电子能谱、扫描电子显微镜、光致发光光谱等方法,表征了ZnO∶Zn荧光薄膜的结构、成分、形貌、发光性能。在ZnO∶Zn荧光薄膜的X射线衍射谱和扫描电子显微镜照片中,可以看出经退火处理后结晶状况大大改善,多晶结构趋于规则,晶粒更加均匀且膜层结构更加致密。在ZnO∶Zn荧光薄膜的光致发光谱中,检测到490 nm处发光峰,认为一价氧空位(VO)充当发光中心,且薄膜的光致发光强度受热处理温度的影响很大。实验表明随着退火温度的升高,薄膜的结晶程度提高,弥补了薄膜晶体表面的表面缺陷,薄膜的发光性能不断提高。

At present, displays, as the medium of people and computer exchange, play an important role. Field emission display （FED） is one of the most promising displays as full color FPD owing to its advantages such as wide view angle, wide temperature range for driving, high picture quality, low power consumption, high response speed, and without magnetic field and X-ray radiation. A lot of obstacles to the success of FED are lack of suitable phosphors, new electron sources for the field emission and encapsulation of FED device. Screens require new luminescent materials and fabricate technology as the one of important segments in FED. It is generally accepted that thin films phosphors have some advantages over bulk-type powder phosphors such as better thermal stability, reduced outgassing, better adhesion, and improved uniformity over the substrate surface. So the research of thin films phosphors becomes a hotspot in the research of FED screen. morphology and luminescence properties of the ZnO ： Zn thin films were performed using X-ray diffraction, X-ray photoelectron spectroscope, scanning electron microscope and photoluminescence spectra. The blue/ green luminescent peak is detected for the ZnO ： Zn thin films. Meanwhile, the singly ionized oxygen vacancies （Vo ） act as luminescent centers and responsible for the visible luminescence which was strongly affected by the annealing processes. It was found that crystallization is improved, and the disfigurement on crystal surface is repaired with the annealing temperature increase. At the same time, it can be concluded that the width of the main peak in photoluminescence spectra increases after the annealing process. The luminescent properties of ZnO ： Zn thin films are enhanced in 400 ℃ and 600 ℃ annealing processes. So it can be concluded that post-deposition annealing is one of effective methods to increase luminescence properties of ZnO ： Zn phosphor thin films.