硫化鎵(GaS)屬於三六族的硫族層狀半導體，由於其優異的電子和光電特性，具有製造於紫外光探測器、場效電晶體、光電元件和光電探測器等高效能光電半導體元件的應用潛力。而本研究利用氣相傳輸法(vapor transport)成功合成鑑定出兩種相異的二維硫化鎵形貌樣品，分別為：出平面奈米牆結構(nanowalls)和平面三角奈米片結構(trigonal nanoflakes)。我們從研究結果中獲得在不同成長溫度下，基板因受到基板表面遷移率以及前驅物濃度多寡影響，當樣品成長溫度為 610 ℃、570℃時，在足夠的蒸鍍量以及較快表面成核速率下會形成較厚且無特定生長方向的奈米牆結構；成長溫度在 550 ℃下的樣品因前驅物濃度降低以及較慢成核速率下會形成平面三角片狀結構。而改變成長壓力(0.3、0.5、1 torr)，是由於抽氣速率的差異而影響試片形貌，研究中發現當成長壓力越大時，氣體擴散能力降低，減緩前驅物沉積到基板上的速率，形成期望的二維平面結構。我們透FE-SEM 分析樣品表面形貌，推測在初期成核成長階段，基板表面都先形成顆粒狀GaS 再結成球狀向上堆疊，彼此間皆以凡得瓦力進行層狀排列。利用 XRD 鑑定樣品之晶體結構，得知兩種結構皆為六方晶系結構且以基板 c 軸方向進行堆疊成長，然而出平面奈米牆結構較無特定方向成長的堆疊，因此相較於平面三角片狀結構多出更多繞射峰訊號。針對三角片狀結構利用 TEM 分析對樣品做顯微結構繞射分析，來確認樣品之成長方向及晶體堆疊方式，最後利用 Raman 光譜分析確認 GaS 三種振動模式且兩者樣品皆為六方晶系，研究結果觀察到其樣品之峰值強度與厚度成相關性，而隨著形貌的變化，E12g在奈米牆結構堆疊的過程中，層與層之間因凡得瓦力相互作用影響，引起結構變化進而影響振動模式，出現紅移；隨著時間減少使得厚度下降，有層數相依性的現象，強度也隨之下降，頻率也有紅移的現象。

Gallium sulfide (GaS) belongs to the III-VI group of layered semiconductor materials and holds great potential for high-performance optoelectronic semiconductor devices due to its excellent electronic and photoelectric properties. In this study, we successfully synthesized and identified two distinct two-dimensional morphologies of GaS using the vapor transport method: nanowalls and trigonal nanoflakes. From the research results, we found that the growth temperature, influenced by the substrate surface migration rate and precursor concentration, plays a significant role in determining the morphology of the samples. At growth temperatures of 610 °C and 570 °C, with sufficient deposition and faster surface nucleation rates, thicker nanowall structures without specific growth orientations were formed. On the other hand, at a growth temperature of 550 °C, the reduced precursor concentration and slower nucleation rate resulted in the formation of planar trigonal flakes. By varying the growth pressure (0.3, 0.5, 1 torr), the sample morphology was found to be affected by differences in the evacuation rate. Higher growth pressures led to reduced gas diffusion capabilities, slowing down the deposition rate of the precursor on the substrate and promoting the desired two-dimensional planar structures. The surface morphology of the samples was analyzed using FE-SEM, revealing that during the initial nucleation and growth stages, the substrate surface first formed GaS particles, which were then stacked upward in a spherical manner, arranged in a layered structure through van der Waals forces. X-ray diffraction (XRD) analysis confirmed that both structures possessed a hexagonal crystal system and grew in the c-axis direction of the substrate. However, the nanowall structure exhibited a less specific growth stacking direction, resulting in more diffraction peak signals compared to the planar trigonal flakes. The growth direction and crystal stacking arrangement of the trigonal flakes were examined using TEM analysis, while Raman spectroscopy confirmed that both structures were hexagonal GaS. The research results observed a correlation between the peak intensity and thickness of the samples, and as the morphology varied, the interlayer van der Waals interactions influenced the structural changes, affecting the vibration modes and resulting in a redshift in the E12g peak. As time progressed and thickness decreased, a layer-dependent phenomenon was observed, with a corresponding decrease in intensity and a redshift in frequency.

謝誌 I
摘要 II
Abstract IV
目錄 VI
圖目錄 X
表目錄 XIV
第 1 章 緒論 1
1.1 前言 1
1.2 研究目標 2
第 2 章 文獻回顧 5
2.1 二維材料的特性與發展 5
2.2 硫化鎵的基本性質 6
2.3 二維硫化鎵的合成 6
2.3.1 化學氣相沉積法(Chemical vapor deposition, CVD) 6
2.3.2 物理氣相沉積法(Physical vapor deposition, PVD) 7
2.3.3 微機械剝離法(Micromechanical exfoliation) 8
2.3.4 脈衝雷射沉積(Pulsed laser deposition, PLD) 8
2.4 硫化鎵晶體能隙與空位缺陷 9
2.5 二維硫化鎵性質與應用 9
VII
2.5.1 層數相依性 9
2.5.2 光電特性 10
第 3 章 實驗步驟與分析儀器 23
3.1 實驗設計 23
3.2 實驗材料 23
3.2.1 實驗儀器 23
3.2.2 基板 23
3.2.3 清潔基板溶液 23
3.2.4 氣相傳輸成長源 23
3.3 實驗步驟 24
3.3.1 清洗基板 24
3.3.2 成長硫化鎵奈米結構 24
3.4 實驗參數 25
3.4.1 改變成長溫度 25
3.4.2 改變成長時間 25
3.4.3 改變硫蒸鍍量 25
3.4.4 改變成長壓力 25
3.5 材料分析儀器 25
3.5.1 場發射掃描式電子顯微鏡(FE-SEM) 25
3.5.2 能量散射光譜儀(EDS) 26
3.5.3 X 光繞射分析儀(XRD) 26
3.5.4 顯微拉曼光譜儀(Micro-Raman Spectroscopy) 27
3.5.5 穿透式電子顯微鏡(TEM) 27
VIII
第 4 章 結果與討論 33
4.1 不同成長溫度 33
4.1.1 表面形貌分析 33
4.1.2 EDS 半定性分析 34
4.1.3 X 光繞射晶體結構分析 34
4.2 不同成長時間 35
4.2.1 表面形貌分析 35
4.2.2 晶體結構與相鑑定 36
4.3 蒸鍍量控制 36
4.3.1 表面形貌分析 36
4.3.2 晶體結構與相鑑定 37
4.4 不同成長壓力 37
4.4.1 表面形貌分析 38
4.4.2 晶體結構與相鑑定 38
4.4.3 半高寬與壓力分析 39
4.5 成長條件與成長機制 39
4.6 TEM 分析 40
4.7 顯微 Raman 光譜分析 41
4.7.1 成長溫度 41
4.7.2 成長時間 42
4.7.3 成長壓力 42
4.7.4 單一片狀硫化鎵 43
第 5 章 結論 59
IX
參考文獻 61

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