成長凡德瓦磊晶透明導電氧化物於可撓式白雲母基板

Abstract

本研究利用凡德瓦磊晶機制,以射頻磁控濺鍍法成長磊晶透明導電氧化物-鋁摻雜 氧化鋅(AZO)於新型態軟性基板-白雲母(Muscovite)上。白雲母為特殊的天然礦物,具 有二維晶格結構,不僅透明可撓,且能承受高溫與強酸強鹼環境,性質遠優於一般軟性 基板,非常適合作為可撓式元件的基材。而作為氧化銦錫(ITO)絕佳替代材料之一,鋁 參雜氧化鋅(AZO)則具有許多優異的性質,並擁有工業應用潛力。本研究分為三部份, 首先以脈衝雷射蒸鍍成長氧化鋅(ZnO),確認可磊晶成長並瞭解製程條件後,再以脈衝 雷射蒸鍍成長 AZO,最後將脈衝雷射蒸鍍 AZO 製程轉移至較適合工業化生產之射頻磁控 濺鍍製程上。而在量測分析方面,對於薄膜晶體結構部分,則透過 X 光繞射與穿透式電 子顯微鏡,分析 ZnO 與 AZO 在白雲母上之原子排列方式,並得到兩者的磊晶關係;另外, 亦以掃描式電子顯微鏡與原子力顯微鏡,了解薄膜之表面形貌;在光學特性與電性部分, 利用紫外光-可見光-近紅外光光譜儀與霍爾效應分析儀,研究 AZO 透明性與導電性,並 與其他文獻互相比較。最後,為了應用於可撓式裝置,本研究也進行撓曲電性分析,包 含於不同彎曲模式下,片電阻隨曲率半徑之變化,與疲勞、時間遲滯測試。研究結果顯 示成長於白雲母上的磊晶鋁摻雜氧化鋅薄膜具有高透光(高於 85%的穿透度)、低電阻(電 阻率約為 1×10-3 Ω∙cm)與耐撓曲等優異特性。由於 AZO/Muscovite 異質磊晶的優異特性, 此可撓式透明導電板有望作為元件開發基礎,促進可撓式裝置的研究,發展成次世代的 電子產品。

This study presents the synthesis of highly conductive, transparent oxide on flexible muscovite mica substrate by Van der Waals epitaxy. Muscovite, a special natural mineral, is a two-dimensional crystal structure. It is not only flexible and transparent but thermal and chemical stable. On the other hand, being a great alternative to indium-tin oxide (ITO), aluminum-doped zinc oxide (AZO) has lots of excellent properties and potential applications in industry. In this study, we grew zinc oxide (ZnO) on muscovite first by Pulsed laser deposition (PLD). After ZnO was successfully grown, AZO was grown on muscovite by PLD. Finally, The PLD process of AZO was shifted to radio frequency magnetron sputtering process which is a more suitable process in industry. The structural characteristics of ZnO/muscovite and AZO/muscovite were analyzed by x-ray diffraction (XRD) and transmission electrical microscopy (TEM). The surface morphologies were revealed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Ultraviolet-visible-Near infrared (UV–Vis– Nir) spectroscopy and Hall-effect analyzer were used to characterize the optical and electrical properties of AZO. In order to make the applications to flexible devices, electrical properties of bending were also investigated. Our research shows that the epitaxial AZO on muscovite has high transmittance (higher than 85%) and low resistivity (around 1×10-3 Ω∙cm), which has a great chance to significantly change the paradigm of flexible, light weight and portable optoelectronic devices.