本研究旨在合成出具有高比表面積之氮化鎵光觸媒，期待能提高光觸媒對有機物的降解效率。
第一部份是利用鎵酸鋰粉末（LiGaO2, LGO）和氧化鎵粉末(Ga2O3) 分別通入氨氣(NH3)作為反應氣體並在高溫下進行化學反應。結果顯示以LGO為初使原料在NH3氛圍下合成的GaN顆粒具有多孔粗糙的表面形貌；而以Ga2O3為初使原料在NH3氛圍下合成的GaN顆粒則是具有光滑的表面。
第二部份則是以LGO粉末做為初使原料，透過改變反應氣體（NH3/H2）來合成出具有高比表面積的GaN粉末。從實驗結果發現：反應溫度930 oC、NH3/H2流量700/700 sccm、NH3/H2通入時間150/150分鐘為合成高比表面積GaN粉末最適合的條件。由XRD圖可知，若以NH3為反應氣體，反應時間必需拉長至720分鐘才能夠使LGO與NH3反應合成GaN粉末，且其微觀形貌呈現較緻密的顆粒狀結構；反觀若將NH3/H2做為反應氣體，則總反應時間可縮短至150分鐘，即可使LGO粉末與NH3/H2完全反應合成GaN粉末，且隨著通入H2時間增加，其微觀形貌逐漸形成疏鬆多孔、片狀叢級的奈米尺度結構，具有高比表面積(S/V ratio)以利於GaN進行光觸媒反應。
進一步針對前兩部份所合成之GaN粉末做分析：光致螢光光譜分析結果發現3種不同表面形貌的GaN粉末其黃光帶發光強度皆大於近能隙發光強度，說明晶體結構中存在著大量缺陷；拉曼分析之E2(High)聲子峰頻率皆為567cm-1，代表晶體結構中無應力存在；TEM結果可明顯觀察出試片編號D2的GaN粉末為結構疏鬆且呈現厚度小於100奈米為類似奈米薄片的結構，具有高比表面積，且HRTEM則顯示出GaN粉末具有良好的結晶性。
光觸媒降解實驗是以亞甲基藍作為污染模擬物，測量在不同照光時間下亞甲基藍之吸收光譜。實驗結果顯示試片編號A3、B1、D2之GaN粉末做為光觸媒其光降解效率分別為60%、40%和70%，即以試片編號D2之GaN粉末做為光觸媒材料對亞甲基藍有最佳的降解效率。

關鍵字：多孔氮化鎵、高比表面積、光觸媒、鎵酸鋰、亞甲基藍

Abstract
The aim of the present study is to synthesize gallium nitride photocatalysis with high specific surface area, which we expect it can promote degradation efficiency to organics.
In phase one of the experiment, we use lithium gallium oxide (LiGaO2, LGO) and gallium oxide (Ga2O3) powders as raw materials, ammonia as reaction gas to conduct the chemical reactions under high temperatures. The results show that the GaN crystal synthesized from LGO raw material under NH3 atmosphere have porous and rough surface morphology; the GaN crystal synthesized from Ga2O3 have rather smooth surface morphology.
In phase two of the experiment, we use LGO powder as raw material. By altering reaction gas (NH3/H2 gas mixture), we synthesize GaN crystal that has high specific surface area.The test results show that: the 930 oC reaction temperature , 700/700 sccm flow rate for NH3/H2 mixed gas and 150 minute flow time for H2 and NH3 are the best parameters to synthesize high specific surface area GaN powder. From XRD we found that if we use NH3 as reaction gas, the reation time has to expand to 720 minutes so the GaN crystal can be synthesized from LGO and NH3. The microcosmic morphology shows condense granular structure. On the other hand, if we use NH3/H2 as reaction gas, the overall reaction time can be reduced to 150 minutes. As we increase the H2 gas flowing time, the microcosmic morphology will become loosen, porous, sheet-like nano-sized cluster that has high specific surface area (S/V ratio), which favors GaN from photocatalyst reaction.
With further investigation. The photoluminescence analysis of GaN powders show that the intensity of yellow-emission band for three different surface morphology are higher than their near-band emission intensities. Indicate there are large amount defect in the crystal structure. The Raman analysis show the E2(high) Phonon peak frequencies were all at 567cm-1, indicate there are no internal stress in crystal structure. From TEM we can see specimen D2 has loosen, flake-like nanostructure with thickness less than 100 nm, shows it has high h/v ratio. The HRTEM image shows the GaN powder has fine crystallinity.
We use methylene blue as pollution analogs for photocatalyst decomposition experiment and measure the absorption spectrum under different exposure time. The results show that the decomposition efficiency of specimen A3, B1, D2 are 60%, 40% and 70% respectively, we derive that specimen number D2 has best degradation efficiency.

Keywords: porous gallium nitride, high specific surface area, photocatalysis, lithium gallium oxide, methylene blue.

論文審定書..................................................................................................i
誌謝............................................................................................................ii
摘要...........................................................................................................iii
Abstract......................................................................................................v
目錄...........................................................................................................vii
圖目錄........................................................................................................x
表目錄.......................................................................................................xii
第一章 前言.........................................................................................1
第二章 文獻回顧................................................................................. 2
2-1 合成GaN粉末文獻回顧......................................................................... 2
2-2 氮化鎵(Gallium nitride, GaN)..................................................................5
2-3 鎵酸鋰(LiGaO2, LGO).......................................................................... 6
2-4 光觸媒.................................................................................................8
2-4-1光觸媒發展歷史...................................................................................8
2-4-2光觸媒簡介.........................................................................................9
2-4-3光觸媒原理.........................................................................................9
2-4-4光化學理論........................................................................................10
2-4-5光觸媒吸附作用..................................................................................11
2-5 亞甲基藍............................................................................................12
2-5-1亞甲基藍基本特性...............................................................................12
2-5-2亞甲基藍之光催化分解........................................................................14
2-6 比爾定律(Beer’s Law)與吸收度(Absorbance) .........................................15
第三章 實驗方法與步驟............................................................................16
3-1 實驗介紹............................................................................................16
3-2 氮化鎵粉末的製備...............................................................................17
3-2-1 鎵酸鋰粉體製備..........................................................................17
3-2-2 氮化步驟....................................................................................18
3-2-3 實驗裝置....................................................................................19
3-3 光觸媒實驗.........................................................................................21
3-4 氮化鎵粉末分析原理與設備...................................................................22
3-4-1 X光繞射分析 (X-ray diffraction, XRD) .............................................22
3-4-2 掃描式電子顯微鏡 (Scanning Electron Microscope, SEM) ..............22
3-4-3 光致螢光光譜儀 (Photoluminescence Spectroscopy, PL) ....................23
3-4-4 拉曼光譜儀(Raman Spectroscopy) ...................................................23
3-4-5 穿透式電子顯微鏡(Transmission Electron Microscope, TEM) ...............23
3-4-6 紫外光-可見光光譜儀 (Ultraviolet/Visible Spectrophotometer, UV-VIS)....24
第四章 實驗結果 .....................................................................................26
4-1 以NH3做為反應氣體合成GaN粉末 ........................................................26
4-1-1 以LGO做為初始原料所合成之 GaN粉末.........................................26
4-1-2 以Ga2O3做為初始原料所合成之 GaN粉末......................................28
4-2 以NH3/ H2做為反應氣體合成之GaN粉末................................................30
4-2-1 不同H2流量對合成GaN粉末的影響 ................................................30
4-2-2 不同H2通入時間對GaN合成的影響.....................................................32
4-3 GaN粉末之表面形貌差異......................................................................35
4-4 PL分析...............................................................................................37
4-5 Raman分析........................................................................................39
4-6 TEM分析............................................................................................41
4-7 GaN粉末光觸媒降解實驗.....................................................................45
第五章 結論............................................................................................50
第六章 參考文獻......................................................................................51

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