發(fā)布時間：2018-02-08 16:37

  本文關(guān)鍵詞： 電弧放電方法 AlN納米結(jié)構(gòu) 四腳ZnO納米結(jié)構(gòu) 生長機制 稀磁半導體　出處：《清華大學》2010年博士論文　論文類型：學位論文

【摘要】：AlN和ZnO低維納米材料和納米結(jié)構(gòu)因其在未來納米器件領域具有廣闊的應用前景而成為納米材料制備與合成研究中一個持續(xù)的熱點,而電弧放電方法在納米材料制備,尤其是復雜納米結(jié)構(gòu)的制備研究中表現(xiàn)出很大的潛力。在此前提下,論文系統(tǒng)地研究了AlN納米材料的電弧放電法制備,并重點探討了實驗中獲得的各種納米結(jié)構(gòu)的生長機制。 論文提出了一種采用電弧放電方法制備稀磁半導體納米材料的新手段,以Al,Co合金鑄錠為原料,在電弧放電過程中,使之與氮氣直接反應生成Co摻雜的AlN納米棒和花狀納米棒陣列,并在VLS模式基礎上分析了它們的生長機制。其中花狀納米棒陣列在室溫和500K的高溫下都表現(xiàn)出明顯的鐵磁性。 在大電流的放電過程中,使純Al塊和氮氣直接反應,制備了獨特的珊瑚狀和羽狀AlN自組裝納米結(jié)構(gòu)。本文提出了一種基于VS模式的兩晶向交替生長機制來解釋羽狀納米結(jié)構(gòu)的形成,并利用氣固相轉(zhuǎn)變中的枝晶生長現(xiàn)象來理解這種復雜的自組裝過程。光致發(fā)光測試表明羽狀AlN納米結(jié)構(gòu)具有良好的可見光發(fā)光性能。 將電弧放電法推廣到ZnO納米結(jié)構(gòu)的制備,通過控制反應氣氛中的氧分壓,制備了從納米顆粒到標準四腳納米結(jié)構(gòu),再到板根狀四腳納米結(jié)構(gòu),這一系列形態(tài)可控的ZnO納米材料。提出了一種中心納米棒生長機制,較好地解釋了新穎的板根狀四腳ZnO納米結(jié)構(gòu)的生長。 在CVD法制備AlN納米材料的對照性實驗中,通過控制反應條件和催化劑的分散方式,制備出了均勻的AlN納米線、項鏈狀AlN納米線和花狀AlN納米線陣列。分析表明,項鏈結(jié)構(gòu)中納米顆粒的表面是由h-AlN晶體中的{1011}組合而成;本文采用一種VLS與VS模式相協(xié)作的生長機制解釋了項鏈狀AlN納米線的形成。通過兩種制備方法產(chǎn)物和生長條件的對比,分析了電弧放電方法的特點。
[Abstract]:AlN and ZnO low-dimensional nanomaterials and nanostructures have become a continuous hot spot in the preparation and synthesis of nanomaterials due to their wide application prospects in the future nanodevices, while arc discharge methods are used in the preparation of nanomaterials. Especially, the preparation of complex nanostructures has great potential. On this premise, the preparation of AlN nanomaterials by arc discharge has been systematically studied, and the growth mechanism of various nanostructures obtained in the experiments has been emphatically discussed. In this paper, a new method of preparing dilute magnetic semiconductor nanomaterials by arc discharge method is proposed. The Al _ (Co) alloy ingot is used as raw material in the process of arc discharge. Co-doped AlN nanorods and flower-like nanorods arrays were synthesized by direct reaction with nitrogen, and their growth mechanism was analyzed on the basis of VLS mode. The flower-like nanorods arrays exhibit obvious ferromagnetism at room temperature and 500K high temperature. In the process of high current discharge, the pure Al block is directly reacted with nitrogen. The unique coral-like and pinnate AlN self-assembled nanostructures were prepared. In this paper, a two-crystal alternating growth mechanism based on vs mode was proposed to explain the formation of pinnate nanostructures. The complex self-assembly process was understood by dendritic growth in gas-solid phase transition. Photoluminescence measurements showed that the pinnate AlN nanostructures had good visible photoluminescence properties. The arc discharge method was extended to the preparation of ZnO nanostructures. By controlling the oxygen partial pressure in the reaction atmosphere, the nanoparticles were prepared from the nanoparticles to the standard tetrapodal nanostructures, and then to the plate root tetrapod nanostructures. A new growth mechanism of central nanorods is proposed, which can explain the growth of novel ZnO nanostructures. In the control experiment of preparing AlN nanowires by CVD method, uniform AlN nanowires, necklace-like AlN nanowires and flower-like AlN nanowires were prepared by controlling the reaction conditions and the dispersion of the catalyst. The surface of the nanoparticles in the necklaces is composed of {1011} in h-AlN crystal. In this paper, the formation of necklace-like AlN nanowires is explained by a growth mechanism of cooperation between VLS and vs mode. The characteristics of arc discharge method are analyzed.
【學位授予單位】：清華大學
【學位級別】：博士
【學位授予年份】：2010
【分類號】：TB383.1

【參考文獻】

相關(guān)期刊論文 前1條

1 ;Morphology-Controlled Growth of A1N One-Dimensional Nanostructures[J];Journal of Materials Science & Technology;2008年04期

，

本文編號：1495886