本研究藉由射頻磁控濺鍍系統進行ZnO:Al透明導電薄膜沉積，分別針對平整ZnO:Al薄膜經真空熱處理前後之結構、表面形貌、顯微組織與光、電特性等方面進行探討，研究中並成功結合奈米球微影技術，使ZnO:Al透明導電薄膜的表面具有碗形-蜂巢狀規則有序之奈米粗糙化結構。 在平整ZnO:Al透明導電薄膜方面，由X光繞射與TEM選區電子繞射可以得知初鍍膜與經真空退火熱處理後的ZnO:Al薄膜為多晶六方晶系結構。TEM橫截面影像更可發現ZnO:Al透明導電薄膜為柱狀晶結構，擇優成長方向為[002]。在X光繞射圖中，經過300-500 ℃真空退火後之ZnO:Al透明導電薄膜，其(002)繞射峰所對應的角度位置，會明顯往高角度偏移。而由ZnO:Al透明導薄膜化學定量元素分析結果顯示，其在薄膜中各化學元素分布相當均勻，且ZnO:Al薄膜經退火前後Zn:O比例皆約1:1。 ZnO:Al透明導電薄膜的電阻率隨退火溫度的提高，會有下降的趨勢。在紫外光-可見光光譜(UV-VIS)中，可觀察到退火後ZnO:Al透明導電薄膜之零度角平均光穿透率與光學能隙會高於初鍍膜ZnO:Al薄膜，且光學能隙會有藍位移的現象。在本研究中，濺鍍功率90 W所沉積之ZnO:Al透明導電薄膜經400 ℃真空退火1小時後擁有最佳的光、電特性，其零度角平均光穿透率與電阻率分別為2.9×10-3 Ω-cm與85.7% (400 nm-800 nm波長範圍)。 表面具有碗形-蜂巢狀規則有序奈米結構之ZnO:Al透明導電薄膜於400 ℃真空退火1小時後，發現其光散射性較平整薄膜可大幅提高。而此種表面具有規則有序奈米結構之ZnO:Al透明導電薄膜，在400 nm-1600 nm波長之光穿透率皆可>80%。此外，在電阻率及FTC (Figure of merit)值之表現上，具有奈米結構的ZnO:Al透明導電薄膜仍保有與平整薄膜相近的結果。 In this study, ZnO:Al transparent conducting oxide thin films were deposited on glass by RF magnetron sputtering system. The structural, surface morphology, mircostructure, optical and electrical properties of flat ZnO:Al thin films before and after annealing have been investigated. In addition, the ZnO:Al films with periodic nonclose-packed, bowl-like nanostructures were successfully fabricated by using the nanosphere lithography (NSL) combined with the sputtering technique. From XRD and SAED analyses, the as-deposited and post-annealed ZnO:Al thin films were poly-crystalline and exhibited hexagonal structure. According to the cross-sectional TEM examinations, it is clearly revealed that the ZnO:Al thin films exhibit preferred orientation of [002] with columnar structures. In the XRD spetra, peak positions of ZnO:Al (002) plane were found to shift slightly toward higher angles after post-annealing at 300-500 ℃. The EDS line-scan profiles clearly demonstrated that the distributions of Zn, O and Al before and after annealing were uniform throughout the ZnO:Al films. Furthermore, the atomic concentrations of Zn and O in the as-deposited sample were found to be the same as that in the 400 ℃ annealed samples. The resistivity of ZnO:Al thin films was found to decrease with increasing annealing temperatures. Based on UV-VIS spectra, both the average transmittance and band-gap energies of annealed ZnO:Al thin films were found to be larger than those of as-deposited samples. The ZnO:Al thin films deposited at 90 W and annealed at 400 ℃ in vacuum for 1 h have the optimal electrical and optical properties. Its resisitivity and transmittance were measured to be about 2.9×10-3 Ω-cm and 85.7% (400 nm-800 nm wavelength), respectively. The light scattering for the 400 ℃ vacuum annealed ZnO:Al thin films with periodic bowl-like nanostructured textures was significantly enhanced. The transmittance of the ZnO:Al thin films with periodic nanostructured textures were > 80% in the ranges of 400-1600 nm. In addition, the resistivity of ZnO:Al thin films with periodic nanostructured textures were similar to that of flat ZnO:Al thin films.
