本研究探討銀摻雜氧化鉬電洞選擇性接觸層應用於網印式單晶矽太陽能電池光電特性之影響，由於氧化鉬(MoOx)有高功函數、電洞選擇性的功能、可藉由本體缺陷來傳導載子及具有較寬的能隙，因而可取代射極鈍化背接觸式(PERC)太陽能電池的背面製程，進一步消除雷射製程上的雷射激光損傷，同時亦可取代具有寄生光吸收損失的異質結構非晶矽薄膜層太陽能電池製程，所以本實驗藉由熱蒸鍍機將銀摻雜至二氧化鉬(MoO2)及三氧化鉬(MoO3)，提升氧化鉬的電特性，在研究中，首先改變氧化鉬中不同的銀含量，在最佳的銀含量參數下，調整摻雜銀後的氧化鉬厚度，接著使用硝酸(HNO3)和氫氟酸(HF)溶液施行拋光製程，探討氧化鉬在拋光面及糙化面對太陽能電池的特性影響，最後探討銀及氧化鉬奈米層的交錯堆疊層效應。
實驗結果顯示，銀摻雜至三氧化鉬比摻雜至二氧化鉬具有較佳的固定負電荷及光電轉換效率，降低銀摻雜三氧化鉬的含量有助於三氧化鉬特性的提升，在適當的銀摻雜三氧化鉬情況下，其厚度為20 nm有較佳的開路電壓、短路電流及光電轉換效率，利用硝酸和氫氟酸溶液進行背表面拋光，並搭配二氧化鉬5 nm，可提升糙化面搭配35 nm的二氧化鉬光電特性，在銀與二氧化鉬交錯堆疊實驗中，二氧化鉬的厚度不能太薄，會降低開路電壓及短路電流，銀的厚度不能太厚會，提高串聯電阻，其交錯堆疊層的數量在4層最佳，實驗結果顯示，當交錯層為4層且二氧化鉬的厚度為1.1 nm搭配銀的厚度為0.2 奈米層可獲得固定負電荷密度為3.13×1013 cm-2、串聯電阻為1.74 Ω-cm2、開路電壓為646 mV、短路電流為36.5 mA/cm2及光電轉換效率為18.57%的太陽能電池元件。

In this study, the effects of silver-doped molybdenum oxide hole-selective contact layers on photovoltaic characteristics of screen-printed monocrystalline silicon solar cells were investigated. The molybdenum oxide (MoOx) with a high work function, hole-selectivity, conducted carriers by bulk defects, and a wider energy gap, can be used to replace the backside process of the passivated emitter and rear contact (PERC) cells. Thus, the laser damage in PERC cells and the parasitic light absorption loss of amorphous silicon in heterojunction thin film solar cells can be eliminated. Thus, in this work, silver-doped molybdenum dioxide (MoO2) and molybdenum trioxide (MoO3) formed by thermal evaporation were used to improve the electrical properties of PERC. First, various silver contents in molybdenum oxide were presented. Under the optimum silver contents, the effects of the thicknesses of the Ag-doped molybdenum oxides were achieved. Furthermore, the polished surface was demonstrated by the mixed HF and HNO3 solutions. Then, the effects of the polished and the textured surface on photovoltaic characteristics of the PERCs with MoOx hole-selective contact layer were addressed. Finally, the effects of the staggered stacked layers with silver and MoOx nano layers were investigated.
The experimental results show that fixed negative charge and photovoltaic conversion efficiency (CE) can be enhanced by the silver-doped MoO3 compared with silver-doped MoO2. The improvement of the characteristics of MoO3 can be achieved by reduced Ag contents in Ag-doped MoO3. Under a suitable Ag-doped MoO3, the open-circuit voltage, short-circuit current, and photovoltaic CE can be improved by the Ag-doped MoO3 with a thickness of 20 nm. The back polished surface was presented by the mixed nitric acid and hydrofluoric acid solution. The electrical properties can be enhanced by the polished surface with a MoO2 of 5 nm compared with the textured surface with a MoO2 of 35 nm. In the multi-stacked films of silver and MoO2, the open-circuit voltage and short-circuit current were reduced by decreasing thickness of MoO2. The series resistance is increased with increasing thickness of silver in multi-stacked films of silver and MoO2. The number of staggered stacked layer was 4 layers. A CE of 18.57 % with an open-circuit voltage (Voc) of 646 mV, a short-circuit current density (Jsc) of 36.5 mA/cm2, a series resistance (Rs) of 1.74 Ω-cm2, and a fixed negative charge density of 3.13 x 1013 cm-2 were demonstrated by the multi-stacked films of 4, a MoO2 of 1.1 nm, and a Ag of 0.2 nm.

摘要............................i
Abstract............................ii
誌謝............................iii
目錄............................iv
表目錄............................vi
圖目錄............................vii
第一章 緒論............................1
1.1過渡金屬三氧化鉬具有電洞選擇性之文獻回顧............................1
1.2金屬摻雜至過渡金屬氧化物之文獻回顧............................2
1.3堆疊層氧化物和銀的薄膜之文獻回顧............................3
1.4研究動機............................5
1.5論文架構............................5
第二章 實驗流程與特性量測............................6
2.1實驗製程............................6
2.1.1去除表面微粒及自然氧化層............................6
2.1.2利用鹼性蝕刻液(KOH)對表面進行糙化(Texturing)............................7
2.1.3藉由高溫爐管對基板進行擴散形成射極層(n+)............................7
2.1.4使用氫氟酸(HF)移除表面磷玻璃(PSG)............................8
2.1.5利用電漿增強型化學氣相沉積系統(Plasma Enhance Chemical Vapor Deposition；PECVD)沉積氮化矽層(SixNy)............................8
2.1.6利用雷射機將試片切割成2×2 cm2............................8
2.1.7對前表面網印(Screen-printing)銀(Ag)電極並且烤乾............................8
2.1.8使用高溫隧道爐進行燒結(Firing)使銀電極刺穿氮化矽層與射極接觸............................9
2.1.9對前表面旋塗聚合物膠體(polymer)並且烤乾作為蝕刻阻擋層............................9
2.1.10使用酸性蝕刻溶液對背表面進行拋光............................9
2.1.11浸泡稀釋氫氟酸(DHF)去除背表面的自然氧化層............................10
2.1.12移除前表面的聚合物膠體............................10
2.1.13利用熱蒸鍍機在P-type矽基板背表面共蒸鍍(Co-evaporation)銀(Ag)和氧化鉬(MoOx)............................10
2.1.14利用熱蒸鍍機在P-type矽基板背表面蒸鍍(Evaporation)銀(Ag)和二氧化鉬(MoO2)的多層堆疊層............................11
2.1.15使用熱蒸鍍機沉積銀(Ag)作為背表面電極............................11
2.2探討銀(Ag)摻雜氧化鉬(MoOx)對於網印式單晶矽太陽能電池之光電特性研究............................12
2.2.1前段實驗製程............................12
2.2.2銀摻雜三氧化鉬的光電特性............................12
2.2.3銀摻雜二氧化鉬的光電特性............................12
2.3藉由堆疊二氧化鉬(MoO2)和銀(Ag)對於網印式單晶矽太陽能電池之光電特性研究............................12
2.3.1不同二氧化鉬厚度於拋光面的光電特性............................12
2.3.2拋光和糙化面堆疊銀和二氧化鉬的光電特性............................13
2.3.3增加堆疊層數及降低銀厚度的光電特性............................13
2.4光伏元件電性分析............................13
2.4.1電流-電壓(I-V)量測系統............................13
2.4.2電容-電壓(C-V)量測系統............................13
2.4.3 外部量子效應(EQE)量測系統............................14
第三章 銀摻雜氧化鉬電洞選擇性接觸層應用於網印式單晶矽太陽能電池光電特性之影響研究............................36
3.1探討銀(Ag)摻雜氧化鉬(MoOx)對於網印式單晶矽太陽能電池之光電特性研究的結果與討論............................36
3.1.1 銀(Ag)摻雜三氧化鉬(MoO3)對光伏元件的電流-電壓(I-V)量測分析............................36
3.1.2 銀(Ag)摻雜三氧化鉬(MoO3)對光伏元件的電容-電壓(C-V)量測分析............................37
3.1.3 銀(Ag)摻雜二氧化鉬(MoO2)對光伏元件的電流-電壓(I-V)量測分析............................39
3.1.4 銀(Ag)摻雜二氧化鉬(MoO2)對光伏元件的電容-電壓(C-V)量測分析............................40
3.1.5 結論............................41
3.2藉由堆疊二氧化鉬(MoO2)和銀(Ag)對於網印式單晶矽太陽能電池之光電特性研究............................42
3.2.1 不同二氧化鉬(MoO2)厚度於拋光面上對光伏元件的電流-電壓(I-V)量測分析............................42
3.2.2 不同二氧化鉬(MoO2)厚度於拋光面上對光伏元件的電容-電壓(C-V)量測分析............................43
3.2.3 拋光和糙化面堆疊二氧化鉬(MoO2)和銀(Ag)對光伏元件的電流-電壓(I-V)量測分析............................43
3.2.4 拋光和糙化面堆疊二氧化鉬(MoO2)和銀(Ag)對光伏元件的電容-電壓(C-V)量測分析............................44
3.2.5 增加堆疊層數及降低銀(Ag)厚度對光伏元件的電流-電壓(I-V)量測分析及外部量子效應(EQE)量測分析............................45
3.2.6 增加堆疊層數及降低銀(Ag)厚度對光伏元件的電容-電壓(C-V)量測分析 45
3.2.7 結論............................46
第四章 總結論與未來展望............................97
4.1 總結論............................97
4.2 未來展望............................97
參考文獻............................98
Extended Abstract............................101

[1] C. Battaglia, X. Yin, M. Zheng, I. D. Sharp, T. Chen, S. Mcdonnell, A. Azcatl, C. Carraro, B. Ma, R. Maboudian, R. M. Wallace, A. Javey, “Hole Selective MoOx Contact for Silicon Solar Cells”, Nano Lett, (2014), Vol 14, pp. 967-971.
[2] M. Bivour, J. Temmler, H. Steinkemper, M. Hermlr, “Molybdenum and Tungsten Oxide: High Work Function Wide Band Gap Contact Materials for Hole Selective Contacts of Silicon Solar Cells”, Solar Energy Materials & Solar Cells, (2015), Vol 142, pp. 34-41.
[3] L. Fang, S. J. Baik, K. S. Lim, “Transition Metal Oxide Window Layer in Thin Film Amorphous Silicon Solar Cells”, Thin Solid Films, (2014), Vol 556, pp. 515-519.
[4] L. G.Gerling, S. Mahato, A. M. Vilches, G. Masmitja, P. Ortega, C. Voz, R. Alcubilla, J. Puigdollers, “Transition Metal Oxides as Hole-Selective Contacts in Silicon Heterojunctions Solar Cells”, Solar Energy Materials & Solar Cells, (2016), Vol 145, pp. 109-115.
[5] D. Ahiboz, H. Nasser, R. Turan, “Admittance Analysis of Thermally Evaporated-Hole Selective MoO3 on Crystalline Silicon”, IEEE Renewable and Sustainable Energy Conference (IRSEC), (2016), pp. 2380-7393.
[6] S. Li, Z. Yao, J. Zhou, R. Zhang, H. Shen, “Fabrication and Characterization of WO3 Thin Films on Silicon Surface by Thermal Evaporation”, Materials Letters, (2017), Vol 195, pp. 213-216.
[7] H. M. Baran, A. Tataroglu, “Determination of Interface States and Their Time Constant for Au/SnO2/n-Si (MOS) Capacitors Using Admittance Measurements”, Chinese Physics B, (2013), Vol 22, pp. 1-5.
[8] L. G. Gerling, S. Mahato, C. Voz, R. Alcubilla, J. Puigdollers, “Characterization of Transition Metal Oxide/Silicon Heterojunctions for Solar Cell Applications”, Applied Sciences, (2015), Vol 5, pp. 695-705.
[9] J. Shi, L. Shen, Y. Liu, J. Yu, J. Liu, L. Zhang, Y. Liu, J. Bian, Z. Liu, F. Meng, “MoOx Modified ITO/a-Si:H(p) Contact for Silicon Heterojunction Solar Cell Application”, Materials Research Bulletin, (2018), Vol 97, pp. 176-181.
[10] C. Battaglia, S. M. D. Nicolas, S. D. Wolf, X. Yin, M. Zheng, C. Ballif, A. Javey, “Silicon Heterojunction Solar Cell With Passivated Hole Selective MoOx Contact”, Applied Physics Letters, (2014), Vol 104, pp. 1-5.
[11] R. A. Vijayan, S. Essig, S. D. Wolf, B. G. Ramanathan, P. Loper, C. Ballif, M. Varadharajaperumal, “Hole-Collection Mechanism in Passivating Metal-Oxide Contacts on Si Solar Cells: Insights From Numerical Simulations”, IEEE Journal of Photovoltaics, (2018), Vol 8, pp. 473-482.
[12] J. Geissbuhler, J. Werner, S. M. D. Nicolas, L. Barraud, A. Hessler-Wyser, M. Despeisse, S. Nicolay, A. Tomasi, B. Niesen, S. D. Wolf, C. Ballif, “22.5% Efficient Silicon Heterojunction Solar Cell with Molybdenum Oxide Hole Collector”, Applied Physics Letters, (2015), Vol 107, pp. 1-5.
[13] Y Wei, K. Yao, X. Wang, Y. Jiang, X. Liu, N. Zhou, F. Li, “Improving The Efficiency and Environmental Stability of Inverted Planar Perovskite Solar Cells Via Silver-Doped Nickel Oxide Hole-Transporting Layer”, Applied Surface Science, (2018), Vol 427, pp. 782-790.
[14] J. Jayabharathi, A. Prabhakaran, V. Thanikachalam, M. Sundharesan, “Hybrid Organic-Inorganic Light Emitting Diodes: Effect of Ag-Doped ZnO”, Journal of Photochemistry and Photobiology A: Chemistry, (2016), Vol 325, pp. 88-96.
[15] C. Ren, B. Yang, M. Wu, J. Xu, Z. Fu, Y. Iv, T. Guo, Y. Zhao, C. Zhu, “Synthesis of Ag/ZnO Nanorods Array with Enhanced Photocatalytic Performance”, Journal of Hazardous Materials, (2010), Vol 182, pp. 123-129.
[16] S. H. Jeong, B. N. Park, S. B. Lee, J. H. Boo, “Metal-Doped ZnO Thin Films: Synthesis and Characterizations”, Surface & Coatings Technology, (2007), Vol 201, pp. 5318-5322.
[17] X. Yu, X. Yu, J. Zhang, D. Zhang, L. Chen, Y. Long, “Light-Trapping Al-Doped ZnO Thin Films for Organic Solar Cells”, Solar Energy, (2017), Vol 153, pp. 96-103.
[18] M. Asemi, M. Ahmadi, M. Ghanaatshoar, “Preparation of Highly Conducting Al-Doped ZnO Target by Vacuum Heat-Treatment for Thin Film Solar Cell Applications”, Ceramics International, (2018).
[19] M. Murugesan, D. Arjunraj, J. Mayandi, V. Venkatachalapathy, J. M. Pearce, “Properties of Al-Doped Zinc Oxide and In-Doped Zinc Oxide Bilayer Transparent Conducting Oxides for Solar Cell Applications”, Materials Letters, (2018), Vol 222, pp. 50-53.
[20] Z. A. Wang, J. B. Chu, H. B. Zhu, Z. Sun, Y. W. Chen, S. M. Huang, “Growth of ZnO:Al Films by RF Sputtering at Room Temperature for Solar Cell Applications”, Solid-State Electronics, (2009), Vol 53, pp. 1149-1153.
[21] J. C. Chang, J. W. Guo, T. P. Hsieh, M. R. Yang, D. W. Chiou, H. T. Cheng, C. L. Yeh, C. C. Li, S. Y. Chu, “Effects of Substrate Temperature on The Properties of Transparent Conducting AZO Thin Films and CIGS Solar Cells”, Surface & Coatings Technology, (2013), Vol 231, pp. 573-577.
[22] L. Hu, Z. Zhang, R. J. Patterson, Y. Hu, W. Chen, C. Chen, D. Li, C. Hu, C. Ge, Z. Chen, L. Yuan, C. Yan, N. Song, Z. L. The, G. J. Conibeer, J. Tang, S. Huang, “Achieving High-Performance PbS Quantum Dot Solar Cells by Improving Hole Extraction Through Ag Doping”, Nano Energy, (2018), Vol 46, pp. 212-219.
[23] W. Wu, J. Bao, Z. Liu, W. Lin, X. Yu, L. Cai, B. Liu, J. Song, H. Shen, “Multilayer MoOx/Ag/MoOx Emitters in Dopant-Free Silicon Solar Cells”, Materials Letters, (2017), Vol 189, pp. 86-88.
[24] T. W. Lin, P. S. Chen, Z. Y. Wang, K. W. Zhuang, S. C. Chiu, C. H. Peng, S. W. Lee, “Tailoring Transparence in MoOx/Ag/MoOx Electrode Through Ag by O2/Ar Plasma Exposure”, Ceramics International, (2017), Vol 43, pp. 308-315.
[25] R. Kan, Y. Yamano, T. Tani, T. Uchida, “MoOx/Ag/MoOx Transparent Electrode by Solution Process”, Japanese Journal of Applied Physics, (2017), Vol 56, pp. 1-5.
[26] B. Tian, G. Williams, D. Ban, H. Aziz, “Transparent Organic Light-Emitting Devices Using a MoO3/Ag/MoO3 Cathode”, Journal of Applied Physics, (2011), Vol 110, pp. 1-6.
[27] T. Abachi, L. Cattin, G. Louarn, Y. Lare, A. Bou, M. Makha, P. Torchio, M. Fleury, M. Morsli, M. Addou, J. C. Bernede, “Highly Flexible, Conductive and Transparent MoO3/Ag/MoO3 Multilayer Electrode for Organic Photovoltaic Cells”, Thin Solid Films, (2013), Vol 545, pp. 438-444.
[28] C. Tao, G. Xie, C. Liu, X. Zhang, W. Dong, F. Meng, X. Kong, L. Shen, S. Ruan, W. Chen, “Semitransparent Inverted Polymer Solar Cells With as Transparent Electrode”, Applied Physics Letters, (2009), Vol 95, pp. 1-3.
[29] J. Bao, W. Wu, Z. Liu, H. Shen, “Silicon Based Solar Cells Using A Multilayer Oxide as Emitter”, Applied Physics Letters, (2016), Vol 6, pp. 1-7.
[30] Y. Wang, B. He, H. Wang, J. Xu, T. Ta, W. Li, Q. Wang, S. Yang, Y. Tang, B. Zou, “Transparent WO3/Ag/WO3 Electrode for Flexible Organic Solar Cells”, Materials Letters, (2017), Vol 188, pp. 107-110.
[31] H. Li, Y. Lv, X. Zhang, X. Wang, X. Liu, “High-Performance ITO-Free Electrochromic Films Based on Bi-Functional Stacked WO3/Ag/WO3 Structures”, Solar Energy Materials & Solar Cells, (2015), Vol 136, pp. 86-91.
[32] L. Shen, Y. Xu, F. Meng, F. Li, S. Ruan, W. Chen, “Semitransparent Polymer Solar Cells Using V2O5/Ag/V2O5 as Transparent Anodes”, Organic Electronics, (2011), Vol 12, pp. 1223-1226.
[33] W. Wu, W. Lin, J. Bao, Z. Liu, B. Liu, K. Qiu, Y. Chen, H. Shen, “Dopant-Free Multilayer Back Contact Silicon Solar Cells Employing V2Ox/Metal/V2Ox as An Emitter”, Royal Society of Chemistry, (2017), Vol 7, pp. 23851-23858.
[34] S. M. Sze, “Physics of semiconductor devices”, J. Wiley, 2nd Edition, New York, 1981.