原子層沉積技術應用於奈米柱陣列與奈米粒子及其光電性質之研究

本論文研究利用原子層沉積技術(Atomic Layer Deposition, ALD)和水熱法(Hydrothermal synthesis)所成長的氧化鋅奈米柱陣列(Nanorod arrays, NRAs)於不同晶種層，與氧化鋅奈米柱陣列在異質接面發光二極體(heterojunction LED)的應用，同時還有研究二氧化鋯(Zirconia, ZrO2)奈米粒子結構的可見光螢光激發光譜(Phololuminescence spectra, PL spectra)。在第二章，控制旋轉塗佈的參數和熱退火處理製作出摻鉺氧化鋅奈米柱，且他們具有強烈的1.54微米紅外線發射光譜。利用該合成方法所合成氧化鋅奈米結構所具有的優勢是能夠進行大規模生產，最低要求的裝備和產品同質化。從螢光激發光譜的測量結果發現，鉺離子被成功地摻入進氧化鋅裡。此外，我們遵循同樣的過程製備摻鉺氧化鋅薄膜。在1.54微米具有增強發光強度的摻鉺氧化鋅奈米柱可期待被利用於光電器件和光通信的應用。在第三章，我們利用原子層沉積技術矽基板上成長兩種不同的氧化鋅晶種層：一個是在氧化鋅晶種層和矽基板中間插入25奈米氧化鎂，另一個是沒有氧化鎂夾層。氧化鎂夾層被證明是有益的，它可以增加氧化鋅晶種層的平均晶粒尺寸。在螢光激發光譜中, 氧化鋅晶種層的發光品質也提升藉由使用氧化鎂夾層。此外，氧化鋅奈米柱成長於在兩個不同的晶種層並對它們的性質進行研究。結果發現，使用氧化鎂夾層, 氧化鋅奈米柱的表面型態會增強, 同時近帶隙(near-band-edge, NBE)發光強度也會提升。期望這章可以提供一個簡單和低溫度的方法去製造高品質的氧化鋅, 且在光電奈米元件的應用。在第四章，我們結合原子層沉積技術和水熱法製作出氧化鋅異質接面發光二極體和氧化鎂電流阻擋層。當正向偏壓增加，來自氧化鋅的電激放光(Electroluminescence)強度有顯著增強，並在室溫下觀察到。此外，結合原子層沉積技術和熱退火處理製作出氧化鋅鎂奈米柱在 p型氮化鎵上形成異質接面發光二極體。在室溫下，光譜中約370 nm處有氧化鋅鎂的電激放光。此章的結果有助於未來實現氧化鋅短波長發光奈米器件。在第5章，均勻分散奈米氧化鋯旋塗直接在矽基板。樣品分為兩部分：氧化鋯奈米粒子和氧化鋅奈米氧化鋯奈米複合材料。經過退火，對氧化鋯奈米粒子和氧化鋅奈米氧化鋯奈米複合材料的可見光螢光激發光譜進行了研究。因此，期望這些氧化鋯奈米結構未來可以有潛力應用於新型環保發光材料。

關鍵字

原子層沉積技術；氧化鋅奈米柱

並列摘要

In this thesis, the optoelectronic characteristics of ZnO NRAs grown by hydrothermal method on different seed layers and their practical applications in heterojunction LED based on p-GaN were investigated. Also, the various UV-visible luminescences from ZrO2 nanoparticles based structures were discovered and proposed. In chapter 2, Er-doped ZnO nanorods with sharp and intense 1.54 µm infrared emission have been synthesized through a well-controlled spin-coating and thermal annealing process. The synthesis method is advantageous for synthesizing ZnO nanostructures capable for large-scale production, minimum equipment requirement and product homogeneity. It was found that Er atoms were successfully incorporate into ZnO host from PL measurements. Furthermore, Er-doped ZnO thin film was fabricated by following the same process, and it was also found that the Er-related emission was not originated from Er2O3 formed on the surface during thermal diffusion process. The enhanced luminescence intensity of Er-doped ZnO nanorods at 1.54µm emission would be conductive to applications in optoelectronic devices and optical communications. In chapter 3, we have grown two different ZnO seed layers by atomic layer deposition (ALD) on Si substrates: One was grown with a 25 nm MgO layer inserted between the ZnO seeds and Si, and the other was grown without any interlayer. The x-ray diffraction measurements revealed that the FWHM of (0002) peak for ZnO seed layer with an inserted MgO layer was sharper than that without an inserted MgO layer, proving that the thin MgO interlayer was useful to increase the average grain size and crystallinity of ZnO seed layer. The characteristic of PL property in ZnO seed layer was also improved significantly using the MgO interlayer. Moreover, the characteristics of ZnO NRAs grown by hydrothermal method on two different seed layers were studied. It was found that ZnO nanorods grown on seed layer with an inserted MgO layer were much larger and longer than that without an inserted MgO layer and showed much stronger NBE emission. No annealing treatment was conducted during the whole experiment for maintaining the sharpness of each layer, so this work may provide a facile and low-temperature route to selective-area fabricate high quality ZnO NRAs for applications in optoelectronic nanodevices. In chapter 4, ZnO NRAs based heterojunction LED with a thin MgO current blocking layer has been fabricated by combining the ALD technique and hydrothermal method. As the applied forward bias increased, light emission from ZnO NRAs showed a significant enhancement in intensity and was observed at room temperature. Moreover, MgZnO NRAs have been successfully fabricated by combining ALD technique and thermal annealing treatment on p-GaN to form the heterojunction LED. At room temperature, EL emission around 370 nm was observed from MgZnO NRAs at a low DC injection current. The results reported in this chapter may assist in the realization of ZnO NRAs based short wavelength light-emitting devices. In chapter 5, monodispersed ZrO2 nanoparticles were spin-coated directly on the Si substrates. The samples were divided into two parts: ZrO2 nanoparticles and ZnO-ZrO2 nanocomposite. The fabrication of ZnO-ZrO2 nanocomposite was followed by the deposition of ZnO by ALD. After being annealed, visible photoluminescence emission from ZrO2 nanoparticles and ZnO-ZrO2 nanocomposite were investigated and characterized. Therefore, these ZrO2 based nanostructures could be potentially applied as new environment-friendly luminescent materials.