以三甲基鎵/第三丁基聯胺之有機金屬化學氣相沉積系統合成直列式氮化鎵奈米線之研究 ; Synthesis of vertically-aligned GaN nanorods using TMGa/TBHy MOCVD system

國立臺灣科技大學化學工程系 ; 學位：碩士 ; 指導教授：洪儒生 ; 本研究利用有機金屬化學氣相沉積(MOCVD)系統，透過「氣-液- 固」機制及使用金當催化劑，成功地在溫度700oC下分別在藍寶石(脉-Al2O3)、矽基板和氮化鎵上成長氮化鎵的奈米線。我們將氮源由傳統MOCVD製程所使用的氨氣(NH3)改為第三丁基聯胺(tertiarybutylhydrazine, TBHy)來與三甲基鎵(trimethyl gallium, TMGa)反應成長一維之氮化鎵奈米線，探討不同的V/III原料供給比、金觸媒厚度、反應時間和材質不同的基材對成長氮化鎵奈米線的影響。 結果發現當成長溫度為700oC，V/III族原料供給比為53.2，以濺鍍法成長了3nm的金觸媒條件下，僅有在GaN基材上才能成長出筆直排列的氮化鎵奈米線，經由XRD分析發現成長方向為C平面的(0001)，其光激發螢光光譜(PL)測量發現奈米線峰值為364.7nm(3.4eV)半高寬為86meV，PL強度比二維的GaN磊晶膜強約39%，顯示基材的晶相特徵決定了成長出的氮化鎵奈米線結晶品質。 我們又利用自組裝製程以控制金核的密度與形態、製作可誘導直列式奈米柱成長的窗口(window)結構期望可得到筆直排列形貌，未來進一步應用在LED的發光元件上。 Vertically-aligned GaN nanorods were successfully grown on gold-coated α-Al2O3(001), Si(111) and GaN(002) substrates by metalorganic chemical vapor deposition (MOCVD). The GaN NWs growth temperature was lowered to 700oC using TBHy alternative to NH3. The precursors of Ga and N were TMGa and TBHy. The diameter and length of GaN nanorods can be controlled by adjusting the V/III ratio, catalyst thickness, reaction time and different substrate. The surface morphology and optical characterization of the grown GaN nanowires were studied by field emission scanning electron micrscope(FE-SEM), photoluminescence(PL), Raman Spectrometer, X-ray diffraction(XRD). A 3 nm-thick sputtered Au catalyst layer, after 700oC annealing, V/III ratio is 53.2, resulted in well vertically-aligned GaN nanorods growth on the GaN substrate. The PL spectra revealed sharp peaks at 364.7nm (3.4eV) with a full width at half maxium (FWHM) of 86meV. Photoluminescence measurement also showed the intensity of band edge emission was 39 % higher than that of the two-dimentional GaN thin film grown on α-Al2O3(001) substrate. respectively, indicating that the grown GaN nanowires were highly crytalline. We try to use different catalyst seeding method, which gold nanoparticles catalyst are continuously self-assembled amine-terminated on 脉-Al2O3 substrate. The diameter and density of GaN nanowires can be controlled by adjusting the size and density of Au nanoparticles.