本工作利用掃描穿隧顯微鏡與掃描穿隧能譜研究N型LaAlO3/TiO2-SrTiO3異質接面的電性特性，同時考慮因探針施加偏壓引起樣品表面能帶彎曲(Tip-induce band bending)的情況，還原原子級尺度LaAlO3/TiO2-SrTiO3的介面能帶圖。
實驗結果指出，LaAlO3內建電場值約為0.075±0.005 V/Å，在異質接面的SrTiO3，接面處能帶有向下彎曲的現象。能帶彎曲變化的能量大小為0.1 eV，能帶彎曲變化的範圍以接面處算起約1 nm。

The electronic structure at interface between two insulators LaAlO3 and SrTiO3 has been investigated by using scanning tunneling microscopy and spectroscopy. The atomic-scale interfacial band structure is also demonstrated in the work with the consideration of the tip-induced band bending effect.
Experimental results indicate that the magnitude of the built-in field across LaAlO3 is 0.075±0.005 V/Å. The band bending on SrTiO3 side at the heterointerface is observed. The band downshift of SrTiO3 side at the interface is 0.1 eV with ~1 nm decay length.

摘要 i
Abstract ii
致謝 iii
目錄 iv
圖目錄 vi
表目錄 ix
第一章 緒論 1
1-1LaAlO3/TiO2-SrTiO3介面電性導電機制 1
1-1-1 介面存在氧缺(Oxygen vacancy) 2
1-1-2 介面電子轉移(Charge transfer) 2
1-1-3 因LaAlO3內建電場(Built-in field) 4
1-1-4 未來應用層面 5
第二章 研究動機 6
第三章 實驗儀器 7
3-1掃描穿隧顯微鏡介紹 7
3-2掃描穿隧顯微鏡原理 8
3-2-1穿隧原理 8
3-3掃描穿隧能譜原理 9
3-4掃描穿隧顯微鏡操作模式 10
3-4-1定電流模式 10
3-4-2定高度模式 10
3-4-3電流密度取像法(Current image tunneling spectroscopy) 11
3-5超高真空系統 11
3-5-1真空計 12
3-5-2真空幫浦 13
3-6探針製作 16
第四章 實驗步驟 17
第五章 結果與討論 18
5-1實驗結果：LaAlO3/TiO2-SrTiO3異質接面的電性特性 18
5-2理論模擬：探針引起能帶彎曲模型(Tip-induced band bending model) 19
5-3實驗討論 22
5-3-1遠離異質接面的SrTiO3電性特性與校正 22
5-3-2靠近異質接面的SrTiO3電性特性與校正 26
5-3-3 LaAlO3內建電場 29
第六章 結論 33
參考文獻 34

1. G. A. Baraff, J. A. Appelbaum, and D. R. Hamann, Phys. Rev. Lett. 38, 237 (1977).
2. W. A. Harrison, E. A. Kraut, J. R. Waldrop, and R. W. Grat, Phys. Rev. B 18, 4402 (1978).
3. A. Tsukazaki et al., Science 315, 1388 (2007).
4. O. Ambacher et al., J. Appl. Phys. 85, 3222 (1999).
5. A. Ohtomo, D. A. Muller, J. L. Grazul, and H. Y. Hwang, Nature 419, 378 (2002).
6. Y. Hotta, T. Susaki, and H. Y. Hwang, Phys. Rev. Lett. 99, 236805 (2007).
7. A. Ohtomo, and H. Y. Hwang, Nature 427, 423 (2004).
8. J. L. Maurice et al., phys. stat. sol. (a) 203, 2209 (2006).
9. M. Basletic et al., Nat. Mater. 7, 621 (2008).
10. S. Thiel et al., Science 313, 1942 (2006).
11. C. W. Schneider et al., Appl Phys. Lett. 89, 122101 (2006).
12. P.R. Willmott et al., Phys. Rev. Lett. 99, 155502 (2007).
13. R. Pentcheva, and W. E. Pickett, Phys. Rev. Lett. 102, 107602 (2009).
14. Z. S. Popovic, S. Satpathy, and R. M. Martin, Phys. Rev. Lett. 101, 256801 (2008).
15. A. Kalabukhov et al., Phys. Rev. B 75, 121404 (2007).
16. G. Herranz et al., Phys. Rev. Lett. 98, 216803 (2007).
17. W. Siemons et al., Phys. Rev. B 76, 155111 (2007) .
18. N. Nakagawa, H. Y. Hwang, and D. A. Muller, Nat. Mater. 5, 204 (2006).
19. J. L. Maurice et al., EPL 82, 17003 (2008).
20. W. J. Son et al., Phys. Rev. B 79, 245411 (2009).
21. J. Lee, and A. A. Demkov, Phys. Rev. B 78, 193104 (2008).
22. K. Yoshimatsu, R. Yasuhara, H. Kumigashira, and M. Oshima, Phys. Rev. Lett. 101, 026802 (2008).
23. G. Singh-Bhalla et al., Nature Phys. 7, 80 (2011).
24. D. F. Bogorin, P. Irvin, C. Cen, and J. Levy, arXiv:1011.5290v1 (2010).
25. R. Jany et al., Appl. Phys. Lett. 96, 183504 (2010).
26. N. Reyren et al., Science 317, 1196 (2007).
27. G. Binning, and H. Roherer, Surf. Sci. 126, 236 (1983).
28. G. Binning, H. Roherer, Ch. Gerber, and E. Weibel, Phys. Rev. Lett. 49, 57 (1982).
29. D. A. Bonnell, Scanning tunneling microscopy and spectroscopy: Theory, Techniques, and Application (VCH Publishers, Inc., New York, 1993).
30. C. J. Chen, Introduction to scanning tunneling microscopy 2nd ed. (Oxford university press, New York, 2007).
31. Ya-Ping Chiu, and Bo-Chao Huang et al.(to be published)
32. V. E. Henrich, G. Dresselhaus, and H. J. Zeiger, Phys. Rev. B 17, 4908 (1978).
33. J. A. Noland., Phys. Rev. 94, 724 (1954).
34. K. W. Blazey, Phys. Rev. Lett. 27, 146 (1971).
35. G. J. de Raad, D. M. Bruls, P. M. Koenraad, and J. H. Wolter, Phys. Rev. B 66, 195306 (2002).
36. R. M. Feenstra, J. Vac. Sci. Technol. B 21, 2080 (2003).
37. R. M. Feenstra, Phys. Rev. B 50, 4561 (1994).
38. K. Janicka, J. P. Velev, and E. Y. Tsymbal, Phys. Rev. Lett. 102, 106803 (2009).