氧化鋅稀磁性半導體薄膜的研究中，最令人感興趣的為氧缺陷所扮演角色。由文獻內容可知，在成長氧化鋅系列薄膜時，若在成長氣氛中混入適量氫氣後，視成長溫度可以產生氫間隙或氧空缺。本研究針對在室溫成長薄膜時，氫氣對純ZnO及Zn0.95Co0.05O產生氧空缺的影響及氧空缺對磁耦合的影響作一系列之研究。
本研究擬成長純ZnO及Zn0.95Co0.05O (CZO)兩系列薄膜。N&K光學分析表明薄膜的光學穿透率隨著混入成長氣體中的氫氣比例增多而下降，代表產生氧空缺濃度也增加。據以往經驗可知，成長氣體的總壓力影響濺鍍粒子的平均自由路徑，間接影響薄膜的厚度，而薄膜厚度影響晶粒品質，同時氧空缺多寡對薄膜導電性具正面效果。研究發現工作總氣壓力為50mTorr的晶粒品質較130mTorr者佳，且因氫氣在薄膜成長過程中產生氧空缺，使得50mTorr成長之薄膜具有較佳的導電性佳。但非常明顯地，成長工作氣體中的氫氣在CZO薄膜中產生氧空缺具有較高的效能。故在相同氫氣百分比的條件下成長之CZO薄膜，具有較高的氧缺陷濃度，進而提升整體導電性；相對的也增加光散射導致具較低之光學穿透率。MCD量數據顯示，此二系列薄膜隨著外加磁場變大時，於3.4ev附近出現明顯之下陷曲線，顯示兩者均具磁性，而且以摻Co之CZO具有較大的磁性。但MCD值與外加磁場關係上呈現順磁行為，並未有室溫鐵磁現象。這說明一件重要事性，即純ZnO雖沒有摻雜磁性離子，但在氧空缺下依然出現磁性，暗示氧空缺本身可能會束縛電子而產生磁矩。

One of the most interested topic in ZnO series diluted magnetic semiconductor is the role of oxygen vacancies. It has been shown that the oxygen vacancies and interstitial hydrogen ions can be generated when introduced hydrogen gas during the film growth depending on the growth temperature. The main goals of this study are to understand the effect of the added hydrogen during the growth of pure ZnO and Zn0.95Co0.05O films on the generation of oxygen vacancies and the effect of oxygen vacancies on magnetic coupling.
Two series of films, ZnO and Zn0.95Co0.05O (CZO) films, were grown by a standard RF sputtering technique. N&K optical measurement indicates the optical transmittance is lower by increasing the percentage of H2 in the growth atmosphere, which is denoted as H2%. Because the total growth pressure may control the mean free path of sputtered particles and indirectly affects films’ thickness which affects the quality of crystal grains. It is found that the crystal quality is better for films grown at 50mTorr rather than that at 130mTorr. The oxygen vacancy may introduce shallow donor band that enhances the electric conductivity, the film grown at 50mTorr has a higher electric conductivity than that at 130mTorr, as well. One important result of present study is that the doping of Co in ZnO films may enhance hydrogen effect and generates more oxygen vacancies in CZO films when were grown at the same growth condition as the pure ZnO films. Therefore, CZO films shows strong optical scattering lowing the optical transmittance. MCD measurements manifest obvious deep curves around 34eV which indicate that both series of films exhibit magnetic coupling under an applied filed, in which, CZO has stronger magnetic strength. However, the MCD is linearly dependent on the external magnetic field indicating a paramagnetic coupling. No room temperature ferromagnetic are observed. One important result is that the existence of magnetic coupling in pure ZnO film indicates that oxygen vacancies may trap electrons and preserved certain magnetic moment.

目錄

致謝---------------------------------------------------------------------------------------- i
摘要---------------------------------------------------------------------------------------- ii
Abstract--------------------------------------------------------------------------------------------------- iii
目錄 ------------------------------------------------------------------------------------------------------- vi
表目錄 --------------------------------------------------------------------------------------------------- viii
圖目錄 --------------------------------------------------------------------------------------------------- viii
第一章 導論-------------------------------------------------------------------------------------------- 1
第二章 理論研究與文獻回顧-------------------------------------------------------------------- 3
2-1氧化鋅性質與結構------------------------------------------------------------------------------- 3
2-2氧化鋅之缺陷介紹與探討--------------------------------------------------- 4
2-3稀磁性半導體發展介紹------------------------------------------------------- 9
2-4ZnO：Co摻雜氫離子效應文獻探討--------------------------------------- 10
2-5磁性機制----------------------------------------------------------------------------- 13
2-5-1RKKY交互作用---------------------------------------------------------------- 13
2-5-2BMP模型------------------------------------------------------------------------ 14
2-5-3變程跳躍(Variable Range Hopping)傳輸同心圓模型------------------- 15
第三章 實驗方法與儀器介紹----------------------------------------------------------- 17
3-1實驗製備與製程---------------------------------------------------------------------- 17
3-1-1靶材製作----------------------------------------------------------------------- 17
3-1-2基板清洗----------------------------------------------------------------------- 18
3-1-3薄膜沉積----------------------------------------------------------------------- 19
3-2射頻磁控濺鍍系統------------------------------------------------------------------- 19
3-2-1儀器架構----------------------------------------------------------------------- 19
3-2-2濺鍍原理與功用-------------------------------------------------------------- 20
3-3量測儀器簡介------------------------------------------------------------------------- 22
3-3-1X光繞射系統（XRD) ------------------------------------------------------- 22
3-3-2N＆K分析儀 1280------------------------------------------------------------ 25
3-3-3磁性圓偏振二向性(MCD) -------------------------------------------------- 26
第四章 結果與討論------------------------------------------------------------------------- 27
4-1氧化鋅薄膜量測---------------------------------------------------------------------- 27
4-1-1光學穿透率分析-------------------------------------------------------------- 27
4-1-2Magnetic Circular Dichroism分析------------------------------------------ 32
4-2氧化鋅摻鈷薄膜量測---------------------------------------------------------------- 39
4-2-1X光繞射學分析--------------------------------------------------------------- 39
4-2-2光學穿透率分析-------------------------------------------------------------- 41
4-2-3Magnetic Circular Dichroism分析------------------------------------------ 45
第五章 結論------------------------------------------------------------------------------------ 50
參考文獻----------------------------------------------------------------------------------------- 51
 
表目錄
表2-1.氧化鋅物理性質--------------------------------------------------------------------------- 3
表4-1.工作氣壓為50mTorr與130mTorr，其MCD位置訊號與強度對應表------- 35
圖目錄
圖2-1.氧化鋅晶體結構：（a) Rock salt（b) Wurtzite（c) Zinc-blende------------------------3
圖2-2.（a)氧化鋅晶體結構（b) 氧化鋅不同晶面示意圖------------------------------------4
圖2-3.經由第一原理的區域密度近似修正計算後，分別於富鋅與富氧情況下，各種缺陷的形成能------------------------------------------------------------------------------ 5
圖2-4.在高鋅分壓條件下，各種形成能經第一原理計算後，得知氧空缺的形成能
相對於其他缺陷形成能低-------------------------------------------------------------- 6
圖2-5.在低鋅分壓條件下，各種形成能經第一原理計算後，得知鋅空缺的形成能
相對於其他缺陷形成能低-------------------------------------------------------------- 7
圖2-6.富鋅情況下，氧化鋅中0、1＋、2＋電荷狀態氧空缺之形成能與費米能階關係圖------------------------------------------------------------------------------------------ 7
圖2-7.氧化鋅纖鋅礦結構示意圖。（a) 黑點表示可能置入位置，BC意味著（bind-center)﹔AB則意味著（anti- bonding)位置。（b)氫的摻入，使得位於BC⊥位置呈現鬆弛狀態----------------------------------------------------------------- 8
圖2-8.各種P型半導體的居禮溫度Tc的理論計算值，其包含5%的錳與每cm3的3.5x1020個電洞-------------------------------------------------------------------------- 10
圖2-9.（a)氫原子鍵結於鈷氧間的原子結構 （b)氫原子鍵結於鈷聚合物所形成的最穩定原子結構------------------------------------------------------------------------- 11
 
圖2-10. ZnCo(9.1％)O：H、ZnCo(5.0％)O：H與ZnCo(4.1％)O、ZnCo(6.1％)O樣品的MCD量測圖----------------------------------------------------------------------- 12
圖2-11.電子能譜儀量測，（a)ZnCo（4.1﹪)O（b)ZnCo（6.1﹪)O（c)ZnCo（5.0﹪)O：H（d) ZnCo（9.1﹪)O：H----------------------------------------------------------------12
圖2-12.RKKY交互作用震盪圖--------------------------------------------------------------- 13
圖2-13.BMP模型-------------------------------------------------------------------------------- 14
圖2-14.不同氧化鋅摻鈷薄膜，隨溫度變化電阻率改變之曲線------------------------ 16
圖2-15.（a) 缺陷、BMP模型與VRH球形相關性（b)不同VR球型間相互作用下，在電性與磁性影響下所發生的鐵磁與反鐵磁行為------------------------------- 16
圖3-1.氧化鋅摻鈷靶材燒結流程-------------------------------------------------------------- 17
圖3-2.基板清洗流程----------------------------------------------------------------------------- 18
圖3-3.濺鍍系統示意圖-------------------------------------------------------------------------- 20
圖3-4.一般射頻濺鍍系統示意圖-------------------------------------------------------------- 21
圖3-5.電子螺旋方向示意圖-------------------------------------------------------------------- 21
圖3-6.X光繞射晶體示意圖-------------------------------------------------------------------- 23
圖3-7.低掠角X光繞射法示意圖--------------------------------------------------------------24
圖3-8.XRD機台簡圖---------------------------------------------------------------------------- 24
圖3-9.N＆K Analyzer1280機台簡圖--------------------------------------------------------- 25
圖4-1.氧化鋅薄膜於不同氫氣含量(0~20%)成長之光學穿透率曲線圖--------------- 28
圖4-2.氧化鋅薄膜於不同氫氣含量(0~30%)成長之光學穿透率曲線圖--------------- 29
圖4-3.氧化鋅薄膜於不同氫氣含量(0~20%)成長之一階微分示意圖------------------ 30
圖4-4.氧化鋅薄膜於不同氫氣含量(0~30%)成長之一階微分示意圖------------------ 30
圖4-5.氧化鋅薄膜於不同氫氣含量(0~20%)與(0~30%)成長之光學能隙示意圖---- 31
 
圖4-6.氧化鋅薄膜於不同氫氣含量(a)0%-20%與 (b) 0%-30%成長之MCD訊號示意圖------------------------------------------------------------------------------------------- 32
圖4-7.氧化鋅薄膜於不同氫氣含量(a)0%-20%與(b) 0%-30%成長之MCD訊號凹點位置處由左至右移動示意圖---------------------------------------------------------- 33
圖4-8.氧化鋅薄膜於不同氫氣含量(0~30%)成長之外加磁場作用下，其MCD訊號
變化示意圖------------------------------------------------------------------------------- 34
圖4-9.氧化鋅薄膜於不同工作壓力成長且於外加磁場作用下，其MCD訊號位置示
意圖---------------------------------------------------------------------------------------- 35
圖4-10.氧化鋅薄膜於相同氫氣含量(0~30%)成長與不同外加磁場作用下，其氧化鋅薄膜MCD訊號示意圖----------------------------------------------------------------- 37
圖4-11.氧化鋅薄膜於相同氫氣含量(0~30%)成長與不同外加磁場作用下，其氧化鋅薄膜MCD訊號示意圖----------------------------------------------------------------- 37
圖4-12.因兩套不同的外加磁場設備，其中固定磁場為0.78T此套設備測量氧化鋅薄膜後的MCD訊號，其對應於不同通入氫氣含量的示意圖--------------- 38
圖4-13.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之低略角X光繞射圖------- 40
圖4-14 .氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之Grain Size 、Lattice Constant of C-axis 與Optical Energy Band Gaps 示意圖------------------ 41
圖4-15.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之光學穿透率曲線圖------- 42
圖4-16.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之特徵吸收示意圖---------- 43
圖4-17.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之一階微分示意圖---------- 44
圖4-18.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長之光學能隙示意圖---------- 45
圖4-19.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長於變磁場下之示意圖------- 46
圖4-20.氧化鋅摻鈷薄膜於相同氫氣含量(2~12%)成長於不同外加磁場訊號疊加示意圖-------------------------------------------------------------------------------------- 48
圖 4-21.氧化鋅摻鈷薄膜於不同氫氣含量(2~12%)成長，其MCD訊號曲線最低值對應於外加磁場之示意圖----------------------------------------------------------- 48
圖4-22.因兩套不同的外加磁場設備，其中固定磁場為0.78T此套設備測量氧化鋅摻鈷薄膜後的MCD訊號最低值，其對應於不同通入氫氣含量的示意圖--49

參考文獻
[1]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）,(2004)。
[2]邱淑琳,“磊晶單雙晶氧化鋅摻雜估稀磁性半導體鐵磁性來源之研究”,國
立成功大學。
[3]S. A. Wolf,“Spintronics: A Spin-Based Electronics Vision for the Future”, Science Vol 294,(2001).
[4]Tomasz Dietl and Hideo Ohno,“Ferromagnetic III–V and II–VI Semiconductors”,(2003).
[5]Nan Zheng,“Introduction to Dilute Magnetic Semiconductors”, Solid Sate II, Instructor(2008).
[6]H. Ohno,“Making Nonmagnetic Semiconductors Ferromagnetic”, Science 281, 951,(1998).
[7]K.W. Edmonds,“Mn Interstitial Diffusion in( Ga,Mn)As”, Phys. Rev. Lett.92,3,(2004).
[8]T. Dietl,“Zener Model Description of Ferromagnetism in Zinc-Blende Magnetic
Semiconductors”, Science Vol 287, (2000).
[9]Kenji Ueda, Hitoshi Tabata, and Tomoji Kawai ,“Magnetic and electric properties of transition-metal-doped ZnO films”,APL. 79, 7,(2001)。
[10]Hiromasa Saeki,Hitoshi Tabata and Tomoji Kawai,“Magnetic and electric properties of vanadium doped ZnO films”, Solid State Communication 120 439-443(2001).
[11]A. F. Kohan, G. Ceder, and D. Morgan, Chris G. Van de Walle,“First-principles study of native point defects in ZnO”, Phys. Rev. B 61,22,(2000).
[12]S. B. Zhang, S.-H. Wei, and Alex Zunger,“Intrinsic n-type versus p-type doping asymmetry and the defect physics of ZnO”, Phys. Rev. B 63, 075205,(2001).
[13]D. C. Look,“Evidence for Native-Defect Donors in n-Type ZnO”, Phys. Rev. Lett .95, 225502 ,(2005).
[14]E. D.Kolb and R.A.Laudise,“Hydrothermally Grown ZnO Crystals of Low and Intermediate Resistivity”,Volume 49,Issue 6,pages 302-305(1966).
[15]Chang-Feng Yu1, Tzu-Jen Lin, Shih-Jye Sun and Hsiung Chou,“Origin of ferromagnetism in nitrogen embedded ZnO:N thin films”, J. Phys. D: Appl. Phys. 40 6497–6500 (2007).
[16]Joon Won Park, Dong Hak Kim, Suk-Ho Choi, Minchul Lee and D. Lim,“The Role of Carbon Doping in ZnO”, Journal of the Korean Physical Society, 57,6 (2010).
[17]H.-J. Lee, C. H. Park, and S.-Y. Jeong,“Hydrogen-induced ferromagnetism in ZnCoO”, APL 88,062504(2006).
[18]Mathew Joseph, Hitoshi Tabata and Tomoji Kawai,“p-type electrical conduction in zno thin films by Ga and N Codoping”, Jpn.J.Appl.Phys Vol.38 pp.L1205-L1207(1999).
[19]Ü. Özgür, Ya. I. Alivov, C. Liu, A. Teke, M. A. Reshchikov et al.,“A comprehensive review of ZnO materials and devices”, J. Appl. Phys. 98, 041301 (2005)。
[20]曹耀中,“氧化鋅摻鈷之稀磁性氧化物薄膜之成長與物性研究”,國立中山大學。
[21]B. H. Choi and H. B. Im,“Thin Solid Films”,193/194, 712 (1990)。
[22]O. Madelung, U. Rossler, M. Schulz (Eds.), Landolt-Börnstein, NewSeries, Group III, 17B, 22a, 41B, Springer, Heidelberg (2006).
[23]黃詠隆,“氧化鋅薄膜之低溫電性傳輸行為研究”,國立交通大學 電子物理學系。
[24]S.Ezhilvalavan,T.R.N.Kutty,“High‐frequency capacitance resonance of ZnO‐based varistor ceramics”,Appl.Phys.Lett,69,3540(1996).
[25]Yanfa Yan and S. B. Zhang,“Control of Doping by Impurity Chemical Potentials: Predictions for p-Type ZnO”, Phys. Rev. Lett.86,25(2001).
[26]D. L. Hou, X. J. Ye, H. J. Meng, H. J. Zhou, X. L. Li, C. M. Zhen, and G. D. Tang,“Magnetic properties of n-type Cu-doped ZnO thin films”, APL.90,142502(2007).
[27]Wensheng Yan, Qinghua Jiang, Zhihu Sun, Tao Yao, Fengchun Hu, and Shiqiang Wei,“Determination of the role of O vacancy in Co:ZnO magnetic film”, Journal of Applied Physics 108, 013901 (2010).
[28]Anderson Janotti and Chris G. Van de Walle,“Oxygen vacancies in ZnO”, Phys. Rev. Lett 87, 122102 (2005).
[29]Chris G. Van de Walle,“Hydrogen as a Cause of Doping in Zinc Oxide”, Phys. Rev. Lett.85.5(2000).
[30]Chris G. Van de Walle and J. Neugebauer,“Universal alignment of hydrogen levels in semiconductors,insulators and solutions”, Nature Vol 423(2003).
[31]Mukul Agrawal,“Magnetic Properties of Materials, Dilute Magnetic
Semiconductors, Magnetic Resonances (NMR and ESR)”,P43.
[32]K. Sato,“Magnetic impurities and materials design for semiconductor spintronics”,Scieence direct Physica B 340–342 (2003) 863–869.
[33]K. W. Edmonds, K. Y. Wang, R. P. Campion, A. C. Neumann, N. R. S. Farley, B. L. Gallagher, and C. T. Foxon“High-Curie-temperature Ga1-xMnxAs obtained by resistance-monitored annealing”, Appl.Phys.Lett 81,26(2002).
[34]S.J. Pearton, D.P. Norton,M.P. Ivill,A.F. Hebard,J.M. Zavada W.M. Chen and I.A. Buyanova,“Ferromagnetism in Transition-Metal Doped ZnO”, Journal of Electronic Materials, Vol. 36, No. 4, 2007.
[35]C. H. Park and D. J. Chadi,“Hydrogen-Mediated Spin-Spin Interaction in ZnCoO”, Phys. Rev. Lett 94, 127204 (2005).
[36]H.-J. Lee, C. H. Park, and S.-Y. Jeong,“Hydrogen-induced ferromagnetism in ZnCoO”, Appl.Phys.Lett 88, 062504 (2006).
[37]M. A. Ruderman And C. Kittel,“Indirect Exchange Coupling of Nuclear Magnetic Moments by Conduction Electrons”, Phys. Rev.96.1(1954).
[38]J. Owen,“Electron and 1Vuclear Spin Resonance and Magnetic Susceptibility Experiments on Dilute Alloys of Mn in Cu”, Phys. Rev.102.6(1956).
[39]T. Kasuya,“A Theory of metallic ferro-and antiferromagnetism on zener model”, Prog. Theor. Phys. 16, 45 (1956).
[40]K.Yosida,“Magnetic Proyerties of Cu-Mn Alloys”, Phys. Rev.106.5(1957).
[41]呂正中,“稀土族介金屬化合物RTX2類型之物理性質研究”,國立成功大學。
[42] http://www.cmp.liv.ac.uk/frink/thesis/thesis/node71.html.
[43]J. M. D. Coey,M. Venkatesan And C. B. Fitzgerald,“Donor impurity band exchange in dilute ferromagnetic oxides”, Nature Materials,Vol4(2005).
[44]H. Chou,C. P. Lin,J. C. A. Huang,and H. S. Hsu1,“Magnetic coupling and electric conduction in oxide diluted magnetic semiconductors”, Phys. Rev. B 77, 245210 (2008).
[45]http://www.core.org.cn/NR/rdonlyres/Physics/8-512Spring2004/2A60E177-E75E-4447-903C-629DAC9DD358/0/lecture_8.pdf.
[46]John C. Sutherland,“Measuurement of Circular Dichroism and Related Spectroscopies with Conventional and Synchrotron Light Sources: Theory and Instrumentation”, Janes, Editors, IOS Press: Amsterdam (2009).
[47]楊孟璇,“低溫濺鍍非晶相ZnO:Al薄膜之研究”, 國立中山大學。
[48]M Fonin, G Mayer1, E Biegger, N Janßen, M Beyer, T Thomay,R Bratschitsch, Yu S Dedkov and U R¨udiger,“Defect induced ferromagnetism in Co-doped ZnO thin films”, Journal of physics：Conference Series 100 (2008), 042034.
[49]C Song, S N Pan1, X J Liu, X W Li, F Zeng, W S Yan, B He and F Pan,“Evidence of structural defect enhanced room-temperature ferromagnetism in
Co-doped ZnO”, J. Phys.: Condens. Matter 19 (2007) 176229.
[50]C.C.Wang, B. Y. Man, M. Liu, C. S. Chen, S.Z. Jiang, S.Y.Yang, S. C. Xu,X.G.Gao, andB. Hu,“The Intrinsic Room-Temperature Ferromagnetism in ZnO:Co Thin Films Deposited by PLD”, Advances in Condensed Matter Physics Volume 2012, Article ID 363981, 5 pagesdoi:10.1155/2012/363981.