臺灣博碩士論文加值系統

氧化亞銅(Cu2O)具有直接遷移型能隙，能隙大約為2.1eV，在可見光區吸收係數大，穿透率低等特性，應用在太陽能電池研製上，將可增大太陽能電池對於入射太陽光的吸收波長範圍。
本實驗使用化學浴沉積法(Chemical Bath Deposition；CBD), 於兩種表面形貌不同的銅基板上進行未摻雜之n型氧化亞銅(undoped Cu2O)薄膜製備研究，並且比較不同回火方式分別為合金爐(RC2400)及紅外線回火(IR-Rurnace)。藉由熱探針法(Hot probe)、光激發螢光頻譜儀(Photoluminescence,；PL)、X-光繞射儀(X-ray diffraction；XRD)、掃瞄式電子顯微鏡(Scanning Electron Microscopy；SEM)、Alpha-step、電流電壓量測系統(Current-Voltage measurement；I-V)去分析薄膜特性。對於不同基板所製備之未摻雜氧化亞銅薄膜，其發光特性主要為1.72eV為二價氧空缺發光，經由高溫回火後出現2.03eV為激子發光(free exciton)，而電容電壓量測(C-V)分析出未摻雜氧化亞銅其載子濃度約為8ⅹ〖10〗^16 〖cm〗^(-3) - 2ⅹ〖10〗^17 〖cm〗^(-3)，利用電容頻率(C-f)與電導頻率(G-f)量測分析並計算出其介面狀態密度(Interface state density distribution；Nss )約3.6378×〖10〗^5 〖cm〗^(-2) 〖eV〗^(-1)-3.08423×〖10〗^8 〖cm〗^(-2) 〖eV〗^(-1)，以SEM分析薄膜表面型態可得知成長於不同表面形貌之基板及不同回火方式，其薄膜之表面型態也不同。

Cuprous oxide is a direct band-gap semiconductor, energy gap size is 2.1eV with a high absorption coefficient in the visible region.
Undoped cuprous oxide (Cu2O) thin films are fabricated on two different surface morphology copper (Cu) substrates by chemical bath deposition (CBD) method. The polycrystalline Cu2O films are annealing by two different tempering systems in nitrogen (N2) at different temperatures, one is alloying furnace (RC2400) and another is IR-Furnace. The Cu2O films are characterized by hot probe measurement, PL, XRD, SEM, Alpha-step and I-V measurement. The optical properties of undoped Cu2O films were investigated by low temperature PL measurement. The obvious peak of undoped Cu2O is 1.72eV. The band at 1.72eV is produced by the recombination of excitons bond to a double charge oxygen vacancies . Using capacitance-voltage measurement to analysis the carriers concentration of n-type undoped Cu2O films and the carriers concentration derived is about 8ⅹ〖10〗^16 to 2ⅹ〖10〗^17 〖cm〗^(-3). Besides, using capacitance versus frequency curves and conductance versus frequency curves to calculate the interface state density distribution of undoped Cu2O. The interface state density distribution with a value of 3.08423×〖10〗^8 〖cm〗^(-2) 〖eV〗^(-1) from (E_c-0.0048) to 3.6378×〖10〗^5 〖cm〗^(-2) 〖eV〗^(-1) from (E_c-0.2698). From the SEM analysis, we can find out that the surface morphology is not the same by using two different substrates and tempering systems.

摘要 I
英文摘要 II
致謝 IV
Content V
Figure Captions VII
Table Captions X
Chapter 1 Introduction 1
1.1 Cu2O material properties 1
1.2 Research motive 3
Chapter 2 Growth and characterization methods 5
2.1 Chemical Bath Deposition 5
2.2 Measurement systems 6
2.2.1 Hot probe 6
2.2.2 X-ray Diffraction 7
2.2.3 Photoluminescence 9
2.2.4 Scanning Electron Microscopy 12
2.2.5 The Current-Voltage measurement 15
2.2.6 Alpha-step measurement 17
Chapter 3 Experiments 18
3.1 Growth of undoped Cu2O films 18
3.2 Annealing effect 21
3.3 Au on undoped Cu2O (Au/Cu2O/Cu) 23
Chapter 4 Results and Discussion 24
4.1 Hot probe 24
4.2 Photoluminescence 26
4.3 X-ray diffraction 31
4.4 I-V measurement 34
4.5 C-V measurement 38
4.6 Alpha-step measurement 47
4.7 Scanning Electron Microscopy 49
Chapter 5 Conclusion 53
Reference 55

List of Figures
Figure 1.1 Correspondence between the absorption spectrum and solar spectrum in the visible region of Cu2O. 2
Figure 1.2 Relationship between theoretical efficiency and the energy gap of solar cells. 3
Figure 2.2.1 Schematic diagram of chemical bath deposition. 5
Figure 2.2.2 Experimental set-up of the hot probe experiment. 6
Figure 2.2.3 Bragg diffraction from planes of atoms in a crystal. 8
Figure 2.2.4 Schematic diagram of photoluminescence system. 10
Figure 2.2.5 Schematic diagram of band-edge photoluminescence process in semiconductor. 11
Figure 2.2.6 Functional diagram of SEM [18]. 14
Figure 2.2.7 The Current-Voltage measurement (Agilent B1500A). 16
Figure 2.2.8 The Current-Voltage measurement. 16
Figure 2.2.9 Schematic diagram of alpha-step system. 17
Figure 3.1 Flow chart of experiments. 20
Figure 3.2 IR-Furnace. 22
Figure 3.3 Alloying furnace (RC2400). 22
Figure 4.1 5K-PL spectra of undoped Cu2O films fabricated on substrate(A): as-grown and performed with RC2400 at different temperatures. 28
Figure 4.2 5K-PL spectra of undoped Cu2O films fabricated on substrate (B): as-grown and performed with RC2400 at different temperatures. 29
Figure 4.3 5K-PL spectra results of undoped Cu2O films fabricated on substrate (A): as-grown and annealed by IR-Furnace at different temperatures. 30
Figure 4.4 XRD patterns of undoped Cu2O films fabricated on substrate (A): as-grown and performed with RC2400 at different temperatures. 32
Figure 4.5 XRD patterns of undoped Cu2O films fabricated on substrate (B): as-grown and performed with RC2400 at different temperatures. 32
Figure 4.6 XRD patterns of undoped Cu2O films fabricated on substrate (A): as-grown and annealed by IR-Furnace at different temperatures. 33
Figure 4.7 Schematic of the Au/Cu2O/Cu contact structure with the top contact pattern clearly demonstrated. 35
Figure 4.8 I-V characteristics of Au/Cu2O/Cu structure where Cu2O film was deposited on substrate (B) and no annealing was performed. 36
Figure 4.9 I-V characteristics of Au/Cu2O/Cu structure where Cu2O film was deposited on substrate (B) and performed with RC2400 at 300℃. 36
Figure 4.10 I-V characteristics of Au/Cu2O/Cu structure where Cu2O film was deposited on substrate (B) and performed with RC2400 at 400℃. 37
Figure 4.11 I-V characteristics of Au/Cu2O/Cu structure where Cu2O film was deposited on substrate (B) and performed with RC2400 at 500℃. 37
Figure 4.12 Plot of 1/C2 vs. V with a section of linear fitting for Au/Cu2O/Cu Schottky diode under reverse bias. 43
Figure 4.13 Plot of 1/C2 vs. V with an extrapolation to the abscissa for extracting the Schottky barrier height (Фb). 43
Figure 4.14 Room temperature C-f curves measured with the forward bias voltage as a parameter for Au/Cu2O/Cu Schottky diode. 44
Figure 4.15 Room temperature G-f curves measured with the forward bias voltage as a parameter for Au/Cu2O/Cu Schottky diode. 44
Figure 4.16 Room temperature Gpω-f curves with the forward bias voltage as a parameter for Au/Cu2O/Cu Schottky diode. 45
Figure 4.17 Nss vs. Ec-Ess for Au/Cu2O/Cu Schottky diode. 45
Figure 4.18 Thickness vs. deposition time for the undpoed Cu2O films prepared by CBD. 48
Figure 4.19 SEM surface images of different Cu substrates. 50
Figure 4.20 SEM images of undoped Cu2O films grown on different substrates: as-grown and conducted with RC2400 treatments. 51
Figure 4.21 SEM images of undoped Cu2O films grown on substrate (A) : as-grown and annealed by different systems. 52

List of Tables
Table 1.1 material properties 2
Table 3.1 The condition of CBD process of undoped Cu2O films with substrate(A) and annealing by RC2400. 19
Table 3.2 The condition of CBD process of undoped Cu2O films with substrate(B) and annealing by RC2400. 19
Table 3.3 The condition of CBD process of undoped Cu2O films with substrate(A) and annealing by IR-Furnace. 19
Table 3.4 The condition of the annealing process. 22
Table 4.1 Hot probe measurements on films deposited on substrate(A) and treated with RC2400. 24
Table 4.2 Hot probe measurements on films deposited on substrate(B) and treated with RC2400. 25
Table 4.3 Hot probe measurements on films deposited on substrate(A) and annealed by IR-Furnace. 25
Table 4.4 The relation between interface states (Nss) and (Ec-Ess). 46

[1] C.A. Dimitriadis, L. Papadimitriou, N.A. Economou, J. Mater. Sci. Lett., 2, 691 (1983).
[2] MAZHARUL M. Islam *, Boubakar Diawara *, Vincent Maurice, Philippe Marcus. Journal of Molecular Structure: THEOCHEM 903 (2004) 41-48.
[3] HAFSA SIDDIQUI, MOHAMMAD RAMZAN PARRA, PADMINI PANDEY, NEHA SINGH, M.S. QURESHI and FOZIA Z. HAQUE. Ultra Engineer Vol. 1(2), 123-135 (2012).
[4] H. Solache-Carranco, G. Juarez-Diaz, A. Esparza-Garcia, M. Briseno-Garcia, M. Galvan-Arellano, J. Martinez-Juarez, G. Romero-Paredes and R. J. Pena-Sierra, J. Lumin. (2009) 129, 1483.
[5] T. Minami, Y. Nishi, and T. Miyata, Appl. Phys. Express, 6, 044101 (2013).
[6] Rakhshani A E, Solid-State Electron, 29, 7 (1986).
[7] C.A.N. Fernando, S.K. Wetthasinghe, Solar Energy Material and Solar Cells, 63 (2000) 299-308.
[8] R. J. Iwanowski and D. Trivich, Phys. Status Solidi A, 95, 735 (2006).
[9] R. G. Delatorre, V. Stenger, V. C. Zoldan, D. L. da Silva, S. G. dos Santos, A. D. C. Viegas, and A. A. Pasa, ECS Trans., 23, 77 (2009).
[10] L. C. Olsen, R. C. Bohara, and M. W. Urie, Appl. Phys. Lett., 34, 47 (1979).
[11] D. K. Zhang, Y. C. Liu, Y. L. Liu, and H. Yang, Phys. B (Amsterdam, Neth.), 351, 178 (2004).
[12] T. Minami, Y. Nishi, T. Miyata, J.-i. Nomoto, Appl. Phys. Express, 4, 062301 (2011).
[13] H. Wei, H. Gong, Y. Wang, X. Hu, L. Chen, H. Xu, P. Liu, and B. Cao, CrystEngComm, 13, 6065 (2011).
[14] S. Noda, H. Shima, and H. Akinaga, J. Phys.: Conf. Ser., 433, 012027 (2013).
[15] F. D. Quarto and S. Piazra, Electrochim. Acta, 30, 315 (1985).
[16] W. Siripala and R. P. Jayakody, Sol. Energy Mater., 14, 23 (1986).
[17] Ji-Wei Ci, Wei-Chen Tu, Wu-Yih Uen, Shan-Ming Lan, Jia-Xian Zeng, Tsun-Neng Yang, Chin-Chang Shen, and Jian-Chang Jhao, J. Electrochem. Soc., 161 (6) D321-D326 (2014).
[18] http://blog.sina.com.cn/s/blog_6c7f960f0100nlnm.html.
[19] Abdu, Y., Musa, A.O. Bayero Journal of Pure and Applied Sciences, 2(2) 8-12 (2009).
[20] Hai Yan Xu, Chen Chen, Ling Xu, Jin Kuang Dong. Thin Solid Films, 527, 76-80 (2013).
[21] G. L*, L. Wang, D. Xue. Materials Letters 64, 2475-2478 (2010).
[22] Mohd Rafie Johan, Mohd Shahadan Mohd Suan, Nor Liza Hawari, Hee Ay Ching, Int. J. Electrochim Sci., 6(2011)6094-6104.
[23] H. Solache-Carranco, G. Juarez-Diaz, A. Esparza-Garcia, M. Briseno-Garcia, M. Galvan-Arellano, J. Martinez-Juarez, G. Romero-Paredes and R. J. Pena-Sierra, J. Lumin. (2009) 129, 1483.
[24] Frazer, Laszlo, et al. "Evaluation of defects in cuprous oxide through exciton luminescence imaging." Journal of Luminescence 159 (2015): 294-302.
[25] Huang, Mao-Chia, et al. "Temperature dependence on p-Cu 2 O thin film electrochemically deposited onto copper substrate." Applied Surface Science301 (2014): 369-377.
[26] Zouaghi, M., et al. "Near infrared optical and photoelectric properties of Cu2O. III. Interpretation of experimental results." physica status solidi (a) 11.2 (1972): 449-460.
[27] Yuki Nishi, Toshihiro Miyata, and Tadatsugu Minami, J. Vac. Sci. Technol. A, 30, 04D103 (2012).
[28] Yuki Nishi , Toshihiro Miyata, Tadatsugu Minami, Thin Solid Films, 528, 72 (2013).
[29] A. O. Musa, T. Akomolafe, and M. J. Carter, Sol. Energy. Mater. Sol. Cells, 51, 305 (1998).
[30] I.S. Yahia, M. Fadel, G.B. Sakr, S.S. Shenouda, F. Yakuphanoglu, J. Mater. Sci. 47 (2012) 1719.
[31] S. Karatas, A. Turut, Microelectron. Reliab. 50 (2010) 351.
[32] A. Ashery, A.A.M. Farag, R. Mahani, Microelectron. Eng. 87 (2010) 2218.
[33] O. Pakma, N. Serin, T. Serin, S. Altindal, Phys. B: Condens. Matter 406 (2011) 771.
[34] Padma, R., B. Prasanna Lakshmi, and V. Rajagopal Reddy. "Capacitance–frequency (C–f) and conductance–frequency (G–f) characteristics of Ir/n-InGaN Schottky diode as a function of temperature." Superlattices and Microstructures 60 (2013): 358-369.
[35] Musa I, Eccleston W. Thin Solid Films 1999;343–344:469–75.
[36]Aydoğan, Ş., M. Sağlam, and A. Türüt. "Characterization of capacitance–frequency features of Sn/polypyrrole/n-Si structure as a function of temperature." Polymer 46.16 (2005): 6148-6153.
[37] Tuğluoğlu, N., F. Yakuphanoglu, and S. Karadeniz. "Determination of the interface state density of the In/p-Si Schottky diode by conductance and capacitance–frequency characteristics." Physica B: Condensed Matter 393.1 (2007): 56-60.
[38] A. Singh, Solid State Electron. 28 (1985) 223.
[39] B. Bati, C. Nuhoglu, M. Saglam, E. Ayyilidiz, A. Turut, Phys. Scripta 61 (2000) 209.
[40] 半導体入門者へのフリー教科書:第４章　ショットキーダイオード.