臺灣博碩士論文加值系統

本論文利用無電鍍蝕刻方法製備準直單晶的矽奈米線，改良其製程並運用於太陽能電池抗反射、場發射與表面增強拉曼上。
在製程改進方面，我們發現，在基板表面刻意加上一層適當厚度的二氧化矽，並且在蝕刻的過程中加上超音波振盪器振盪，可使矽奈米線變得緻密且均勻。
在抗反射方面，我們在不同長度的奈米線樣本測量抗反射效果。發現奈米線長約2μm，在可見光的範圍中的抗反射效率平均可達2%以下。該抗反射特性，應與蝕刻過程導致奈米線由空氣層到矽基板之空間平均填充率漸次變化，形成等效漸變折射率有關。
在表面增強拉曼散射應用上，我們利用奈米線的高表面積，蒸鍍銀顆粒在奈米線上，並量測R6G的拉曼訊號。我們發現其拉曼增強訊號可達到約2.5x107倍，證實矽奈米線可作為表面增強拉曼的基板。
在場發射特性的量測中，我們發現奈米線越長場發射的特性越好，長約3.6μm的奈米線可得到最佳的臨界電場約14.3V/µm。此臨界電場，相較於碳奈米管(~2V//µm)仍偏高，推測可能是因為奈米線相互緊鄰，產生屏蔽效應(Screen effect)，我們建議可利用黃光微影製程將奈米線形成陣列，加以改進。

In the present thesis, the subject of interest is to improve the fabrication process of well-aligned silicon nanowires (SiNWs) made through electroless etching, as well as to applied SiNWs to solar cell anti-reflection, field emission and surface enhanced Raman scattering.
We improved the fabrication process of SiNWs by preforming a SiO2 layer on the substrate followed by ultrasonic violating the etching solution including AgNO3 and HF. Apparently better uniformity and less defect density in SiNWs fabricated with the improved process were attained. To investigate the potential application of SiNWs in solar cell, the antireflection properties of SiNWs with different lengths were studied. The result showed that SiNWs with about 2μm in length gave the lowest reflectance (<2% in the broad visible band). The effective graded index between air and silicon substrate could be responsible for the broad band anti-reflection of the SiNWs. To use the SiNWs as a high surface area substrate for surface-enhanced Raman scattering measurement, we deposited Ag particles on the SiNWs and measure the Raman signal from R6G. An Raman enhanced factor of 2.5x107 was attained on Ag coated SiNWs compared to that estimated on a plane silicon substrate without silver, proving the SiNWs an effective substrate for surface enhanced Raman scattering measurement. The field emission properties of the SiNWs were also studied. It was found that SiNWs with longer lengths basically showed better performance in filed emission. For example, SiNWs with a length of 3.6µm, showed the lowest threshold electrical field at 14.3V/µm. However, the threshold filed, compared to that for carbon nanotube (~2V/µm), was still quite high. The high threshold field could be a result of screen effect due to the high density of nanowires getting to close to each other. For further improvement of the threshold filed, fabrication of SiNWs in arrays using lithographic techniques was recommended.

圖表目錄 IX
表格目錄 XI
方程式目錄 XII
第一章 緒論 1
第二章 工作原理與文獻探討 4
2-1 無電鍍金屬沉積與蝕刻技術之工作原理 4
2-2 太陽能電池與抗反射原理 6
2-3 表面增強拉曼散射與增強幅度的計算 9
2-4 場發射原理與F-N曲線 12
第三章 實驗流程、步驟與設備 15
3.1 實驗流程與步驟 16
3.1.1 矽奈米線製備流程 16
3.1.2 無電鍍蝕刻機制製作奈米線 17
3.1.3 製作奈米線參數 18
3.1.4 表面增強拉曼散射製程 19
3.1.4.1 蒸鍍銀膜 19
3.1.4.2 配製Rodimine 6G溶液 19
3.1.5 其他應用 20
3.1.5.1 KOH溶液控制奈米線濃度 20
3.1.5.2 樹技狀的矽奈米線 20
3.1.5.3 狼牙棒狀的矽奈米線 20
3.2 實驗儀器簡介 20
3.2.1 濕蝕刻系統 20
3.2.2 表面結構與材料分析 21
3.2.2.1 原子力顯微鏡(AFM) 21
3.2.2.2 掃描式電子顯微鏡(SEM ) 22
3.2.2.3 X-Ray光譜儀(XRD) 23
3.2.3 光學特性分析儀器 24
3.2.3.1 UV/VIS/IR光譜儀 24
3.2.3.2 拉曼光譜儀 24
3.2.3.3 場發射電壓與電流量測系統 25
3.2.4 氧化系統 28
3.2.4.1 高溫爐 28
3.2.5 鍍膜系統 28
3.2.5.1 濺鍍機系統 28
3.2.5.2 蒸鍍機 29
第四章 結果與討論 30
4.1 製程改進及矽奈米線之表面結構 30
4.1.1 蝕刻前後矽奈米線基板表面比較 30
4.1.2 製程改進前後之缺陷形貌圖 31
4.1.2.1 缺陷形成之原因與解決方法 31
4.1.3 銀樹枝狀沉積物 33
4.1.4 矽奈米線之表面結構 35
4.1.5 無電鍍蝕刻機制之蝕刻比例 38
4.2 表面增強拉曼散射特性 40
4.2.1 不同雷射功率時的R6G拉曼訊號圖 40
4.2.2 矽奈米線基板的SEM照片 42
4.2.3 矽奈米線基板的拉曼訊號 45
4.2.4 和不同長度的奈米線比較 47
4.2.5 和不同基板的比較 48
4.2.5.1 有鍍銀的矽奈米線與矽基板之間增強幅度的比較 48
4.2.5.2 有鍍銀的矽基板與奈米線對沒鍍銀的矽基板之間增強幅度的比較 50
4.3 抗反射特性在太陽能電池上的應用 52
4.3.1 矽奈米線的抗反射特性 52
4.3.1.1 n-type(100)矽奈米線 52
4.3.1.2 n+-type(100)的矽奈米線 56
4.4 場發射特性 58
4.4.1 兩種量測場發射訊號的基座 58
4.4.1.1 玻璃作為陰陽極間距離的基座 58
4.4.1.2 使用單軸移動平台製作的場發射基座 62
4.5 其他實驗 65
4.5.1 利用KOH控制奈米線的密度 65
4.5.2 樹技狀的矽奈米線 67
4.5.3 狼牙棒狀的矽奈米線 68
第五章 結論 71

[1] Z. Y. Wang, Z. B. Zhao, J. S. Qiu, Progress in Chemistry 18, 563(2006)
[2] J. X. Zhou, M. S. Zhang, J. M. Hong, Z. Yin, Solid State Communications 138, 242(2006)
[3] M. Hayashi, L. Thomas,Y. B. Bazaliy, C. Rettner, R. Moriya, X. Jiang, S. P. Parkin, Physical Review Letters 96, 197207(2006)
[4] J. B Chang, J. Z. LiuZ, P. X. Yan, L.F. Bai, Z.J. Yan, X.M. Yuan and Q. Yang, Materials Letters 60, 2125(2006)
[5] J. B. Hannon, S. Kodambaka , F. M. Ross, R. M. Tromp, NATURE 440, 69(2006)
[6] N. Fukata, T. Oshima, N. Okada, T. Kizuka, T. Tsurui, S. Ito and K. Murakami, PHYSICA B-CONDENSED MATTER 376, 864(2006)
[7] K. W. Adu, H. R. Gutierrez, U. J. Kim, P. C. Eklund, PHYSICAL REVIEW B 73, 15533(2006)
[8] K. Peng, Y. J. Yan, S. P. Gao, J. Zhu, Adv. Mater. 14, 1164(2002)
[9] K. Peng, Y. J. Yan, S. P. Gao, J. Zhu, Adv. Funct. Mater. 13, 127 (2003).
[10] K. Peng, J. Zhu, Journal of Electroanalytical Chemistry 558, 35 (2003).
[11] K. Peng, J. Zhu, Electrochimica Acta 49, 2563 (2004).
[12] K. Peng, Z. Huang, J. Zhu, Adv. Mater. 16, 73 (2004).
[13] K. Peng, Y. Wu, H. Fang, X. Zhong, Y. Xu, J. Zhu, Angew. Chem. Int. Ed. 44, 2737 (2005).
[14] K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, J. Zhu, SMALL 1, 1062(2005)
[15] K. Peng, J. J. Hu, Y. J. Yan, Y. Yan, Y. Wu, H. Fang, Y. Xu, S. T. Lee, J. Zhu, Adv. Funct. Mater. 16, 387(2006)
[16] T. Qiu, X. L. Wu, X. Yang, G. S. Huang, Z. Y. Zhang, Appl. Phys. Lett. 84, 3867 (2004).
[17] T. Qiu, X. L. Wu, Y. F. Mei, G. J. Wan, P. K. Chu, G. G. Siu, Journal of crystal growth 277, 143 (2005).
[18] T. Qiu, X. L. Wu, Appl. Phys. Lett. 86, 193111 (2005).
[19] J. Zhao, A. Wang, M.A. Green, IEEE, 333 (1990).
[20] J. M. Woodall and H. J. Hovel, “Outlooks for GaAs Terrestrial Photovoltaics,” J . Vac. Sci. Technol. 12, 1000 (1975).
[21] J. H. Rose, M. Chency, B. Defacio, Physial Review Letters 57, 783 (1986)
[22] A. Otto, I. Mrozek, H. Grabhorn, W. J. Akemann, J. Phys. Chem. Condens. Matter 4, 143 (19920)
[23] M. Moskovits, Rev. Mod. Phys 57, 783(1985)
[24] G. B. Alexandre, E. I. Donald, D. S. Brian, Journal of Molecular structure, 405, 29 (1997)
[25] K. Katrin, K. Harald, I. Irving, R. D. Ramachandra, S. F. Michael, Chem. Rev. 99, 2957 (1999)
[26] S. B. Chaney, S. Shanmukh, R. A. Dluhy, Y. P. Zhao, Appl. Phys. Lett. 87, 031908-1 (2005).
[27] B. R. Huang, J. F. Hsu, C. S. Huang, Diamond and Related Materials 14, 2105 (2005)
[28] L. Gunnarsson, E. J. Bjerneld, H. Xu, S. Petronis, B, Kasemo, M, Kall, Appl. Phys. Lett. 78, 802 (2001)
[29] L. H. Christy, P. V. Richard, J. Phys. Chem. B, 107, 7426(2003)