指導老師：林克默 博士 學 生：楊顯奕 報告日期： 2010.10.24

OutlineOutline1 Introduction2 Experimental procedure3 Results and discussion4 Conclusion

IntroductionIntroductionTransparent conducting films have attracted much attention as a

transparent electrode according to the development of liquid crystal display, plasma display panel, organic electroluminescence,solar cells, etc.

The transparent conducting film should have low resistivity, high transmittance in the visible range and high stability against heat [1,2]. Indium tin oxide film as a transparent conducting film has widely used because of its good electrical and optical properties. However, it has some problem such as high cost, low stability to H2 plasma and toxicity. On the other hand, ZnO film has a lot of advantages,such as low cost, non-toxicity and high stability in H2 plasma atmosphere with good electrical and optical properties [3].

In the present study, Al-doped ZnO (AZO) films were prepared on glass substrate by the sol–gel spin coating method using homogeneous and stable zinc acetate dihydrate-isopropanol-monoethanolamine sol doped with 1 at.% Al with respect to Zn. The crystal orientation, electrical and optical properties with post-deposition heating temperature were investigated.

Experimental procedureExperimental procedureZinc acetate dehydrate (Zn(CH3COO)22H2O) and

aluminum chloride hexahydrate (AlCl36H2O) were dissolved in a solution of isopropanol and monoethanolamine. The molar ratio of MEA to zinc acetate was 1.0 and the concentration of zinc acetate was 0.7 mol/l. The concentration of Al as a dopant was of 1.0 at.% with respect to Zn. The resultant solution was stirred at 50°for 1 h to yield a clear and homogeneous solution.

The solution was finally aged at room temperature for 24 h. Al-doped ZnO (AZO) films were prepared on glass (Corning Inc. 7059) substrate by repeated coating. Spin coating was performed at room temperature, with a rate of 3000 rpm for 20 s. After depositing each times, the films were preheated in air at 275 ° for 10 min. After repeating the coating procedure five times for the final film thickness of approximately 250 nm,the films were finally postheated at 500, 550, 600, 650 and 700 ° for 1 h in air using an electronic furnace.

Fig. 1. SEM micrographs of Al-doped ZnO films postheated at various temperatures of (a) 500°C, (b) 550°C, (c) 600°C, (d) 650°C and (e) 700°C.

Results and discussionResults and discussion

Fig. 2. XRD patterns of Al-doped ZnO films postheated at various temperatures.

Fig. 2 shows XRD patterns of the AZO films preheated at275 8C and postheated at 500–700 8C. All the AZO films have a preferred orientation along the (0 0 2) plane, and no Al peaks are detected.

Fig. 3. Crystallite size of Al-doped ZnO films.

where D is the crystallite size, k, a fixed number of 0.9, l, the Xray wavelength, u, the Bragg’s angle in degrees and B, the full width at half maximum of the (0 0 2) plane

Fig. 4. (a and b) XPS spectra of Al-doped ZnO films postheated at various temperatures.

Fig. 5. Optical transmittance spectra (a) and (ahn) vs. hn plot based on the transmittance spectra (b) of Al-doped ZnO films postheated at various temperatures.

Fig. 6. Resistivity of Al-doped ZnO films postheated at various temperatures.

ConclusionsConclusions鋁摻雜氧化鋅薄膜的玻璃基板上製備的溶膠凝膠旋塗法和電器及光學特性對薄膜的沉積後加熱溫度的影響。均勻的，穩定的溶膠製備醋酸鋅溶解在溶液中異丙醇和單乙醇胺。沿（ 0 0 2）方向增強了隨沉積後加熱溫度，薄膜表面均勻，呈奈米級的微觀結構。該薄膜的電阻率下降，從 73到 22 歐姆時為後退火製程加熱溫度提高到 650度。

然而，薄膜電阻率在 700度後退火製程大幅增加至580 歐姆 c 後退火製程低於 650度透光率超過86%,在 700度會下降 AZO的光學特性和電的退化，在後退火製程似乎是隔離在 Al2O3 晶界和部分孔隙。