臺灣博碩士論文加值系統

本研究中，我們利用固態燒結法製備摻雜碳的二氧化鈦粉末，再使用油壓機和箱形爐來對粉末加壓和加熱，使其成為塊材。接著我們使用脈衝雷射鍍膜系統進行鍍膜，並在一系列成長條件下探討碳掺雜對二氧化鈦磁性造成的效應和機制。我們發現摻雜碳的二氧化鈦有明顯的磁滯曲線，顯示碳摻雜確實會形成室溫鐵磁性。本論文藉由C-1s和Ti-2p之XPS量測，發現薄膜中有鈦和碳的鍵結與氧空缺，顯示摻碳二氧化鈦的鐵磁性來源，是由氧空缺與雜質間相互作用所產生。從O-1s的XPS也可以看出，摻雜碳可使氧空缺變多，此可能進而產生更多電子。本實驗也發現隨著碳的掺雜濃度增加，鐵磁性並未維持一直增加的趨勢，甚至反而減弱材料的室溫鐵磁性，本論文亦將對此現象，提出初步的解釋。

Carbon-doped titanium dioxide powders was prepared by solid state sintering at 1200 o C for 24hrs to produce TiO2 bulks with different carbon doping concentrations. The obtained TiO2 bulks were then used to deposit TiO2 thin films by pulsed laser deposition. The effects of carbon doping was investigated via a series of films obtained at various deposition conditions. The results indicate that the carbon-doped titanium dioxide evidently exhibit significant magnetization hysteresis at room temperature, indicating the realization of room-temperature ferromagnetism (RTFM).
Further X-ray photoelectron spectroscopy (XPS) analysis on C-1s, O-1s, and Ti-2p electronic states showed the existence of Ti-C bonding and significant
amount of oxygen vacancies. These results lend support to the p-p interaction, induced ferromagnetism in these oxides. The observed RTFM, however, did not increase with increasing doping concentration of carbon, presumably due to the excessive free carbon-induced diamagnetism.

Contents
Abstract (in Chinese) i
Abstract (in English) ii
Acknowledgement iv
Contents vi
List of Figures viii
Chapter 1 Introduction 1
1-1 Magnetic materials and semiconductors 1
1-2 Diluted Magnetic Semiconductors (DMSs) 3
1-2.1: What’s DMS 3
1-2.2: Types of DMSs 5
1-2.3: The development of DMSs 8
1-2.4: Why DMSs are so important? 14
1-3 Titanium dioxide 15
1-3.1: Photocatalyst 15
1-3.2: Literature review of TiO2 16
1-3.3: The crystal structure of titanium dioxide 23
1-3.4: TiO2-based materials 25
1-3.5: 2p-light element doped DMSs 26
1-4 Motivation 28
Chapter 2 Background 29
2-1 Brief introduction to magnetism 29
2-2 Types of magnetism 32
2-3 The mechanism and source of magnetism in DMSs 38
2-3.1: Bound magnetic polaron (BMP) 42
2-3.2: Mechanism of exchange interaction 44

Chapter 3 Experiments and Instruments
48
3-1 Sample preparation 48
3-1.1: Target fabrication 48
3-1.2: Pulsed laser deposition (PLD) 49

3-2 Structure analysis by XRD 50
3-3 Analysis of magnetism 51

3-3.1: Introduction of the SQUID 51
3-3.2:The principle of Josephson junctions 53
3-4 Surface electronic structure analysis 54
3-4.1: What’s X-ray Photoelectron Spectroscopy? 54
3-4.2: Chemical State Identification 55

3-5 X-ray absorption near edge structure (XANES) 57

hapter 4 Results and discussion
60
4-1 The characteristics of carbon-doped TiO2 powders 60
4-1.1:Structure Analysis of powders by X ray Diffraction(XRD) 60
4-1.2:Magnetic analysis of powders by SQUID 61

4-2 The characteristics of carbon-doped TiO2 thin films 64
4-2.1:Structure analysis of thin films by X-ray Diffraction 64
4-2.2:Magnetic analysis of thin films by SQUID 66
4-3 Surface electronic structure analysis by XPS 67
4-4 Diamagnetic effect caused by excessive carbon 72
4-5 XANES analysis 74
Chapter 5 Conclusions 76
References 78

[1] 黃榮俊, 自旋電子之研究與發展, 物理雙月刊（廿六卷四期）.
[2] 胡裕民, III-V稀磁性半導體薄膜之研究與發展, 物理雙月刊（廿六卷四期）.
[3] H. Ohno, Science 281, 951 (1998).
[4] J. K. Furdyna and J. Kossut, Diluted Magnetic Semiconductors, vol. 25 of Semiconductor and Semimetals (Academic Press, New York, 1988); T. Dietl, (North-Holland, New York, 1994).
[5] A. Haury , A. Wasiela , A. Arnoult , J. Cibert , S. Tatarenko , T. Dietl , and Y. Merle d'Aubigné , Phys. Rev. Lett.79, 511 (1997).
[6] Toshio Kamiya and Masashi Kawasaki: MRS Bulletin, 33, 1061-1066, (2008).
[7] N. S. Gillis*,T. R. Koehler, Phys. Rev. Lett. 29, 369–372 (1972).
[8] H. Munekata, H. Ohno, S. von Molnar, Armin Segmüller, L. L. Chang, and L. Esaki, Phys. Rev. Lett. 63, 1849(1989).
[9] T. Dietl, H. Ohno, F. Matsukura, J. Cibert, D. Ferrand, Science 287, 1019 (2000).
[10] Sato K and Katayama-Yoshida H, Japan. J. Appl. Phys. 39 L555 (2000).
[11] Matsumoto Y, Murakami M, Shono T, Hasegawa T, Fukumara T, Kawasaki M, Ahmet P, Chikyow T, Koshihara S Y and Koinuma H, Science 291 854 (2001).
[12] M. L. Reed, N. A. El-Masry, H. H. Stadelmaier, M. K. Ritums, M. J. Reed, C. A. Parker, J. C. Roberts, and S. M. Bedair, Appl. Phys. Lett. 79, 3473 (2001).
[13] M.L. Reed a, M.K. Ritums a, H.H. Stadelmaier a,), M.J. Reed a, C.A. Parker b, S.M. Bedair b, N.A. El-Masry a , Mater. Lett. 51, 500 (2001).
[14] Saki Sonodaa*, Saburo Shimizua, Takahiko Sasakib, Yoshiyuki Yamamotob, Hidenobu Horia, J. Crystal Growth 237-239, 1358 (2002).
[15] M. Hashimoto, Y.K. Zhou, H. Tampo, M. Kanamura, H. Asahi*, J. Crystal Growth 252, 499 (2003).
[16] Kenji Ueda, Hitoshi Tabata, and Tomoji Kawa, Appl. Phys. Lett. 79, 988 (2001).
[17] Parmanand Sharma et al. , J. Magn. Magn. Mater. In Press, Uncorrected Proof, Available online 5 May 2004.
[18] R. A. de Groot , F. M. Mueller , P. G. van Engen and K. H. J. Buschow , Phys. Rev. Lett. 50, 2024 (1983).
[19] S. M. Watts, S. Wirth, S. von Molnár , A. Barry and J. M. D. Coey , Phys. Rev B 61, 9621 (2000).
[20] J.-H. Park, E. Vescovo, H.-J. Kim, C. Kwon, R. Ramesh & T. Venkatesan
, Nature 392, 794, (1998).
[21] J. J. Versluijs, M. A. Bari, J. M. D. Coey, Phys. Rev. Lett. 87, 026601 (2001).
[22] K.-I. Kobayashi*, T. Kimura*, H. Sawada*, K. Terakura* & Y. Tokura* , Nature 395, 677 (1999).
[23] R P Borges, R M Thomas, C Cullinan, J M D Coey, R Suryanarayanan, L Ben-Dor, L Pinsard-Gaudart and A Revcolevschi, J. Phys.: C M 11, 445-L450 (1999).
[24] Y.Matsumoto, M. Murakami,T. Shono, T.Hasegawa,T. Fukumura,M. Kawasaki, P. Ahmet, T.Chikyow, S.-Y. Koshihara, and H. Koinuma, Science, 291, 854 (2001)
[25] S. A. Chambers, S. Thevuthasan, R. F. C. Farrow, R. F. Marks, J. U. Thiele, L. Folks, M. G. Samant, A. J. Kellock, N. Ruzycki, D. L. Ederer, and U. Diebold, Appl. Phys. Lett. 79, 3467 (2001).
[26] W. K. Park, R. J. Ortega-Hertogs, J. Moodera, A. Punnoose, and M. S. Seehra, J. Appl. Phys. 91, 8093 (2002).
[27] Yuji Matsumoto, Ryota Takahashi, Makoto Murakami, Takashi Koida, Xiao-Juan Fan, Tetsuya Hasegawa, Tomoteru Fukumura, M. Kawasaki, Shin-Ya Koshihara and Hideomi Koinuma,, Jpn. J. Appl. Phys., Part 2 40, L1204 (2001).
[28] Y. Matsumoto, M. Murakami, T. Hasegawa, T. Fukumura, M. Kawasaki, P. Ahmet, K. Nakajima, T. Chikyow, and H. Koinuma, Appl. Surf. Sci. 189, 344 (2002).
[29] S. A. Chambers, T. Droubay, C. M. Wang, A. S. Leab, R. F. C. Farrow, L.
Folks, V. Deline, and S. Anders, Appl. Phys. Lett. 82, 1257 (2003).
[30] A. Punnoose, M. S. Seehra, W. K. Park and J. S. Mooera, J. Appl. Phys. 93,7867 (2003).
[31] R. J. Kennedy and P. A. Stampe Erhong Hu, Peng Xiong, and Stephan von Molna and Yan Xin, Appl. Phys. Lett. 84, 2832 (2004).
[32] Nguyen Hoa Hong, Joe Sakai, and Awatef Hassini, Appl. Phys. Lett. 84, 2602 (2004).
[33] K. A. Griffin, A. B. Pakhomov, C. M. Wang, S. M. Heald, and Kannan M. Krishnan, Phys. Rev. Lett. 94,157204 (2005).
[34] Nguyen Hoa Hong, W. Prellier, Joe Sakai, and Awatef Hassin, Appl. Phys. Lett. 84, 2850 (2004).
[35] Mariana Weissmann, Leonardo A. Erric, P R B. 398, 179 (2007).
[36] S. J. Wang, W.-T. Chang, J.-Y. Ciou, M.-K. Wei*, and M. S. Wong, “Preparation of TiO2 thin films by laser ablation for photocatalytic applications”, J. Vac. Sci. Technol. A, Vol. 26, 898-902 (2008).
[37] Tang H, Berger H, Schmid P E and Levy F 1994 Solid State Commun. 92 267
(1994).
[38] Hsieh C C, Wu K H, Juang J Y, Uen T M, Lin J-Y and Gou Y S 2002 J. Appl. Phys. 92 2518 (2002).
[39] Murakami M, Matsumoto Y, Nakajima K, Makino T, Segawa Y, Chikyow T, Ahmet P, Kawasaki M and Koinuma H 2001 Appl. Phys. Lett. 78 2664 (2001).
[40] Kennedy R J and Stampe P A 2003 J. Cryst. Growth 252 333 (2003).

[41] Parker N J, Kharel P, Powell J R, Smith P A, Evans P D and Porch A 1999 IEEE Trans. Appl. Supercond. 9 1928 (1999).
[42] Zuccaro C, Ghosh I, Urban K, Klein N, Penn S and Alford N M 1997 IEEE Trans. Appl. Supercond. 7 3715 (1997).
[43] Augustynski J 1993 J. Electronchim. Acta 38 43 (1993).
[44] W.Prellier, A.Fouchet and B.Mercey, J.Phys.: Condens. Matter. 15 R1583-R1601 (2003).
[45] C.-F. Yu, T.-J. Lin, S.-J. Sun, and H. Chou, J. Phys. D 40, 6497 (2007).
[46] H. Pan, J. B. Yi, L. Shen, R. Q. Wu, J. H. Yang, J. Y. Lin, Y. P. Feng, J. Ding, L. H. Van, and J. H. Yin, Phys. Rev. Lett. 99, 127201 (2007).
[47] S. Zhou, Q. Xu, K. Potzger, G. Talut, R. Groetzschel, J. Fassbender, M. Vinnichenko, J. Grenzer, M. Helm, H. Hochmuth, M. Lorenz, M. Grundmann, and H. Schmidt, Appl. Phys. Lett. 93. 232507 (2008).
[48] J. J. Attema, G. A. de Wijs, G. R. Blake, and R. A. de Groot, J. Am. Chem. Soc. 127, 16325 (2005).
[49] L. Shen, R. Q. Wu, H. Pan, G. W. Peng, M. Yang, Z. D. Sha, and Y. P. Feng, Phys. Rev. B 78, 073306 (2008).
[50] Kesong Yang, Ying Dai, Baibiao Huang, and M. H. Whangbo, Appl. Phys. Lett. 93, 132507 (2008).
[51] Abdul K. Rumaiz, J. C. Woicik, E. Cockayne, H. Y. Lin, G. Hassnain Jaffari, and S. I. Shah, Appl. Phys. Lett. 93, 262111 (2009).
[52] J. M. D. Coey, Kwanruthai Wongsaprom, J. Alaria, and M. Venkatesan, J. Phys. D: Appl. Phys. 41, 134012 (2008).
[53] 宛德福、馬興隆，磁性物理學，電子工業出版社 (1999).
[54] 戴道生、錢昆明等等，鐵磁學，科學出版社 (2000).