本研究是在P-type 矽晶片上沉積一層鋁薄膜,利用水溶液法於醋酸 鋅、氯化鋅與硝酸鋅前驅物溶液中,藉由改變溫度、時間與SDS 的添 加量,製備柱狀氧化鋅,從實驗結果可以得到以下的結論:
1. 醋酸鋅與氯化鋅前驅物溶液中,於沉積溫度低與沉積時間短的情況 下,所生長的沉積膜之表面形貌皆為樹枝狀結構,隨著SDS 的添加,
沉積膜表面形貌會變為層狀、絨絲狀或蜂窩狀結構。於常溫與時間 3 hrs 下,沉積膜的表面形貌都是柱狀結構, 當 SDS 的添加量為 14.4 mg 時,皆會變成橢圓柱狀結構,而 SDS 過量(28.8 mg)時,其表面 形貌可能為蜂窩狀、柱狀與蜂窩狀結構共存。上述這些結構,除了 柱狀與橢圓狀結構是氧化鋅之外,其餘形貌皆是鋅,且這些結構都 是Hcp。
2. 硝酸鋅前驅物溶液中,於沉積溫度低與沉積時間短的情況下,所生 長的沉積膜之表面形貌皆為豌豆狀結構,隨著SDS 添加時,低溫的 條件會形成帶狀結構,而時間短的時候會形成蜂窩狀結構。於常溫 與時間3 hrs 下,沉積膜的表面形貌是樹枝狀結構,當 SDS 添加量 為14.4 mg 時,會變成柱狀結構,而 SDS 為 28.8 mg 時,則會變成 蜂窩狀結構。這些結構中,除了柱狀結構是氧化鋅之外,其餘形貌
皆是鋅,且這些結構都是Hcp。
3. 沉積溫度太低或沉積時間太短,溶液中的 Zn2+及 OH-無足夠能量與 時間跟鋁薄膜反應形成氧化鋅,此時溶液中的反應還是以氧化還原 為主,只能得到鋅,而不是氧化鋅。且適量添加SDS 推估是能產生 氧化鋅,但是SDS 添加過量時,鋅與氧化鋅的異質成核位置皆會增 加,可是溶液中早就有一部份 Zn2+與鋁薄膜進行氧化還原反應,把 Zn 還原出來,因此反而會抑制氧化鋅的生成。
4. 濃度 5 mM 的醋酸鋅、氯化鋅與硝酸鋅前驅物溶液中,於常溫與時 間 3 hrs 下,無論是否有添加 SDS,其產物成分皆只有鋅與氧的訊 號,且添加 SDS 之沉積膜的鋅比例皆比未添加 SDS 之沉積膜的鋅 比例來的高,顯示添加SDS 確實能夠促進鋅與氧化鋅的成長。
5. 無論在醋酸鋅、氯化鋅或硝酸鋅前驅物溶液中所成長之柱狀或橢圓 柱狀氧化鋅,經XPS 分析可知,其 Zn 2p3/2的訊號與Zn 2P1/2訊號分 別在1022.2 eV 與 1045.2 eV 附近,與 Hand-book 上所記載 Zn 2p3/2 在1022.5 eV 的位置,只差了 0.3 eV,且 Zn 2p3/2的訊號與Zn 2P1/2 的差值為23.0 eV,亦接近文獻的差值 23.1 eV,而氧的訊號也和文 獻上的531.5 eV 相近,因此可得知沉積膜確實是氧化鋅。
6. 光學性質方面,在醋酸鋅、氯化鋅與硝酸鋅前驅物溶液,且成長條
只有在2.28 eV(綠光區)有 PL 訊號存在,是因為氧化鋅內部有大 量的氧格隙缺陷(Oi)。而柱狀氧化鋅在 2.38 eV(綠光區)與 3.06 eV
(紫外光區)的位置各有一 PL 訊號產生,分別是氧化鋅內部的氧 對位缺陷(OZn)與鋅空位缺陷(VZn)造成的。推估水溶液法搭配鋁薄膜 所成長之橢圓柱狀及柱狀氧化鋅可能因為沉積系統能量不足,造成 氧化鋅內部有大量的氧格隙、氧對位及鋅空位缺陷,使氧化鋅之PL 訊號不在理論的3.37 eV 附近出現。
7. 橢圓柱狀與柱狀氧化鋅,經過 TEM 影像分析後,顯示兩者皆是由許
多尺度更小的奈米線管束(直徑大約2 ~ 4 nm)所叢聚而成的。
8. 研究中所推導的化學反應式,說明水溶液中 Zn2+、OH-與鋁薄膜之 間進行氧化還原反應而生成氧化鋅,推估鋁因為還原電位比鋅大,
所以能有效降低氧化鋅形成的活化能,進而降低製程溫度。成長機 制解釋SDS 在水溶液中形成微球囊狀結構,進而吸附 Zn2+,形成氧 化鋅的成核點,進而促使柱狀氧化鋅的成長。
第六章 未來展望
本研究已成功利用水溶液法,於常溫下,藉由改變界面活性劑SDS 的添加量,在醋酸鋅、氯化鋅與硝酸鋅水溶液中製備柱狀奈米氧化鋅,
不過仍然有一些議題我們可以進一步去研究與改進:
1. 在基板上沉積其他氧化電位(活性)更高的薄膜,增加與水溶液中 鋅正離子及氫氧根負離子的作用而形成氧化鋅。
2. 利用不同的退火方式,有效的增加氧化鋅的結晶性和去除雜質,增 加氧化鋅於光學方面的應用。
3. 大面積化具有氧化鋅奈米結構,因為是常溫製程,可應用於製備可 撓式的色素增感太陽能電池之陽極。
4. 結合氧化鋅奈米結構與奈米碳管形成奈米複合體,探討奈米複合體 於其他性質方面的特性與應用。
5. 可藉由調整製程參數,使鋁原子能佔據氧化鋅內部的格隙位置,形 成氧化鋅掺雜鋁(Al-doped ZnO)之薄膜,而應用於透明導電薄膜。
參考文獻
A
1. Alivisatos, A. P., J. Phys. Chem., 100 (1996) 13226, “Perspectives on the physical chemistry of semiconductor nanocrystals”.
2. Asfold, M. N. R.,F. Claeyssens, G. M. Fuge, and S. Henley, Chem. Soc. Rev., 33 (2004) 23, “Pulsed laser ablation and deposition of tjin films”.
B
3. Buhro, W. E., T. J. Trentler, K. M. Hickman, S. C. Goel, A. M. Viano, and P. C.
Gibbons, Science, 270 (1995) 1791, “Solution-liquid-solid growth of crystalline III-V semiconductor: an analogy to vapor-liquid-solid growth”.
C
4. Caldeira, A. O., and A. J. Legget, Phys. Rev. Lett., 46 (1981) 211, “Influence of dissipation on quantum tunneling in macroscopic systems”.
5. Cao, B., W. Cai, G. Duan, Y. Li, Q. Zhao, and D. Yu, Nanotechnology, 16 (2005) 2567, “A template-free electrochemical deposition route to ZnO nanoneedle arrays and their optical and field emission properties”.
6. Chen, P. L., R. S. Muller, R. D. Jolly, G. L. Halac, R. M. White, A. P. Andrews, T.
C. Lim, and M. E. Motamedi, IEEE Trans. Electron Dev., 29 (1982) 27, “Integrated silicon microbeam PI-FET acelerometer”.
7. Chen, Y., D. M. Bagnall, H. J. Koh, K. T. Park, K. Hiraga, Z. Zhu, and T. Yao, J.
Appl. Phys. Lett., 84 (1998) 3912, “Plasma assisted molecular beam epitaxy of ZnO c-plane sapphire: growth and characterization”.
8. Chen, M., Z. L. Pei, X. Wang, C. Sun, and L. S. Wen, J. Vac. Sci. Technol., 19 (2001) 963, “Structural, electrical, and optical properties of transparent conductive oxide ZnO: Al film prepared by dc magnetron reactive sputtering”.
9. Claeyssens, F., C. L. Freeman, N. L. Allan, Y. Sun, M. N. R. Ashfold, and J. H.
Harding, J. Mater. Chem., 15 (2005) 139, “Growth of ZnO thin film-experiment and theory”.
10. Claude, L. C., T. Z. Ramon, M. A. Ryan, A. Katty, and G. Hodes, Adv. Mater., 17 (2005) 1512, “CdSe-sensitized p-CuSCN/nanowire n-ZnO heterojunction”.
D
11. Dong, L., D. W. Tuggle, J. M. Petty, S. A. Ellif, and M. Coulter, Appl. Phys. Lett., 82 (2003) 1096, “ZnO nanowires formed on tungsten substrates and their electron field emission properties”.
E
12. Eranna, G., B. C. Joshi, D. P. Runthala, and R. P. Gupta, Crit. Rev. Solid State Mater. Sci., 29 (2004) 111, “Oxide materials for development of integrated gas sensor-A comprehensive review”.
F
13. Fan, H. J., P. Werner, and M. Zacharias, Small, 6 (2006) 700, “Semiconductor nanowires: from self-organization to pattered growth”.
G
14. Gratzel, M., Science, 414 (2001) 338, “Photoelectrochemical cells”.
15. Gruber, D., F. Kraus, and J. Müller, Sens. Actuators B, 92 (2003) 81, “A novel gas sensor design based on CH4/H2/H2O plasma etched ZnO thin films”.
16. Guo, M., P. Diao, and S. Cai, J. Solid State Chem., 178 (2005) 1864, “Hydrothermal growth of well-aligned ZnO nanorod arrays: dependence of morphology and alignment ordering upon preparing conditions”.
J
17. Jalochowski, and M., E. Bauer, Phys. Rev. B, 38 (1988) 5272, “Quantum size and surface effects in the electrical resistivity and high-energy electron reflectivity of ultrathin lead films”.
K
18. Kim, E. S., and R. S. Muller, IEEE Electron. Dev. Lett., 10 (1987) 467,
“IC-processed piezoelectric microphone”.
19. Kobayashi, H., S. Kawamoto, Y. Sakai, P. L. Choyke, R. A. Star, M. W. Brechbiel, N. Sato, Y. Taagaya, J. C. Morris, and T. A. Waldmann, J. Natl. Cancer Inst., 96 (2004) 703, “Lymphatic drainage imaging of breast cancer in mice by micro-magnetic resonance lymphangiography using a nano-size paramagnetic contrast agent”.
L
20. Lakin, K. M., and J. S. Wang, Appl. Phys. Lett., 38 (1981) 126, “Acoustic bulk wave composite resonators”.
21. Landes, C. F., S. Link, M. B. Mohamed, B. Nikoobakht, and M. A. Ei-Sayed, Pure Appl. Chem., 74 (2002) 1675, ”Some properties of spherical and rod-shapped semiconductor and metal nanocrystals”.
22. Law, M., J. Goldberger, and P. Yang, Annu. Rev. Mater. Res., 34 (2004) 83,
“Semiconductor nanowires and nanotubes”.
23. Law, M., L. E. Greene, J. C. Johnson, R. Saykallyi, and P. Yang, Nat. Mater., 4 (2005) 455, “Nanowire dye-sensitized solar cell”.
24. Lee, W., M. C. Jeong, and J. M. Myoung, Acta Mat., 52 (2004) 3949, “Catalyst-free growth of ZnO nanowires by metal-organic chemical vapor deposition (MOCVD) and thermal evaporation”.
25. Lin, B., Z. Fu, Y. Jia, and G. Liao, J. Electrochem. Soc., 148 (2001) G110, ”Defect photoluminescence of undoping ZnO films and its dependence on annealing conditions”.
M
26. Marathe, S. K., P. M. Koinkar, S. S. Ashtaputre, M. A. More, S. W. Gosavi, D. S.
Joag, and S. K. Kulkarni, Nanotechnology, 17 (2006) 1932, ”Efficient field emission from chemically grown inexpensive ZnO nanoparticles of different morphologies”.
27. Mohamed, M. B., C. Burda, and M. A. El-Sayed, Nano Lett., 1 (2001) 589, “Shape dependent ultrafast relaxation dynamics of CdSe nanocrystals: nanorods vs nanodots”.
N
28. Nandi, S. K., S. Chatterjee, S. K. Samanta, G. K. Dalapati, P. K. Bose, S. Varma, S.
Patil, and C. K. Maiti, Bull. Mater. Sci., 26 (2003) 365, “Electrical properties of Ta2O5 films deposited on ZnO”.
O
29. Ohno, Y., D. K. Young, B. Beschoten, F. Matsukura, H. Ohno, and D. D.
Awschalom, Nature, 402 (1999) 790, “Electrical spin injection in a ferromagnetic semiconductor heterostructure “.
P
30. Pauzauskie, P.J., and P. Yang, Mater. Today, 9 (2006) 36, “Nanowire photonics”.
31. Pearton, S.J., D. P. Norton, K. Ip, Y. W. Heo, and T. Steiner, Prog. Mater. Sci., 50 (2005) 293, “Recent progress in processing and properties of ZnO”.
S
32. Shields, A. J., M. P. O’Sullivan, I. Farrer, D. A. Ritchie, R. A. Hogg, M. L.
Leadbeater, C. E. Norman, and M. Pepper, Appl. Phys. Lett., 76 (2000) 3673,
“Detection of single photons using a field- effect transistor gated by a layer of quantum dots”.
T
33. Tachibana, K., T. Someya, Y. Arakawa, R. Werner, and A. Forchel, Appl. Phys.
Lett., 75 (1999) 2605, “Room-temperature lasing oscillation in an InGaN self-assembled quantum dot laser”.
34. Tang, Z. K., G. K. L. Wong, P. Yu, M. Kawasaki, A. Ohtomo, H. Koinuma, and Y.
Segawa, Appl. Phys. Lett., 72 (1998) 3270, ”Room-temperature ultraviolet laser emission from self- assembled ZnO microcrystallite thin films”.
U
35. Usui, H., J. Phys. Chem. C, 111 (2007) 9606, “Influence of surfactant micelles on morphology and photoluminescence of zinc oxide nanorods prepared by one-step chemical synthesis in aqueous solution”.
V
36. Vayssieres, L., Adv. Mater., 15 (2003) 464, “Growth of arrayed nanorods and nanowires of ZnO from aqueous solution”.
W
37. Wagner, R. S., and W. C. Ellis, Appl. Phys. Lett., 4 (1964) 89, “Vapor-liquid-solid mechanism of single crystal growth”.
38. Webster, T. J., M. C. Waid, J. L. Mckenzie, R. L. Price, and J. U. Ejiofor, Nanotechnology, 15 (2004) 48, “Nano-biotechnology: carbon nanofibres as improved neural and orthopaedic implants”.
39. Wiel, W. G. V. D., S. De Franceschi, J. M. Elzerman,T. Fujisawa, S. Tarucha, and L.
P. Kouwenhoven, Rev. Mod. Phys., 75 (2003) 1, “Electron transport through double
40. Wu, J. J., and S. C. Liu, Adv. Mater., 14 (2002) 215, “Low-temperature growth of well-aligned ZnO nanorods by chemical vapor deposition”.
X
41. Xia, Y., P. Yang, Y. Sun, Y. Wu, B. Mayers, B. Gates, Y. Yin, F. Kim, and H. Yan, Adv. Mater., 15 (2003) 353, “One-dimensional nanostructures: synthesis, characterization, and application”.
42. Xu, J., Q. Pan, Y. Shun, and Z. Tian, Sens. Actuators B, 66 (2000) 277, “Grain size control and gas sensing properties of ZnO gas sensor”.
Y
43. Yang, P., Y. Wu, and R. Fan, Int. J. Nanosci., 1 (2002) 1, “Inorganic semiconductor nanowires”.
44. Yi, G. C., C. Wang and W. I. Park, Semicond. Sci. Technol., 20 (2005) S22, “ZnO nanorods: synthesis, characterization and applications”.
45. Yin, H., Z. Xu, Q. Wang, J. Bai, and H. Bao, Mater. Chem. Phys., 91 (2005) 130,
“Study of assembling ZnO nanorods into chrysanthemum-like crystals”.
46. Yoon, D. H., and G. M. Choi, Sens. Actuators B, 45 (1997) 251, “Microstructure and CO sensing properties of porous ZnO produced by starch addition”.
Z
47. Zhang, H. D. Yang, X. Ma, Y. Ji, J. Xu, and D. Que, Nanotechnology, 15 (2004) 622, “Synthesis of flower-like ZnO nanostructures by an organic-free hydrothermal process”.
48. 施敏、張俊彥,”半導體元件物理與製作技術”,高立圖書有限公司,2001,P.131.
49. 郭正次、朝春光,”奈米結構材料科學”,全華科技圖書股份有限公司,2004,
P.6-2, 8-8, 8-15.
個人簡歷
電子信箱:[email protected] 學歷