臺灣博碩士論文加值系統

利用電漿輔助式分子束磊晶法 (PA-MBE) 在鈉鈣玻璃上成長倒置型硒化銅鋅錫 (CZTSe) 薄膜太陽能電池。此太陽能電池的吸收層為 CZTSe 、無鎘緩衝層為硒化鋅摻雜鎵 (ZnSe:Ga) 、透明導電膜為氧化鋅錫薄膜 (ZTO) 。由於高品質ZTO適合於高溫環境成長，而CZTSe薄膜適合於低溫環境成長，所以將其成長方式順序顛倒以免後續的高溫製程破壞吸收層的特性。成長的順序首先成長透明導電膜，其次是緩衝層與吸收層，最後再加上金屬背電極即完成元件結構。我們分層分析各層的特性。ZTO 薄膜同時成長在C軸藍寶石 (c-sapphire) 與鈉鈣玻璃基板上。在X光繞射分析圖譜中，可觀察到成長在C軸藍寶石與鈉鈣玻璃基板上的ZTO都是非晶的結構。此外，我們發現在玻璃上的ZTO薄膜平均粗糙度(0.9 nm)比在C軸藍寶石小(1.5 nm)。藉由四點探針量測分析，ZTO成長在玻璃上的電阻率小於在C軸藍寶石上。根據測量的結果，意味著此元件僅需使用玻璃基版製作。而在ZTO上成長的ZnSe:Ga，其電性上最低的電阻率與最大的載子濃度分別為1.16 x10-2 Ω-cm 以及1.58x1020 cm-3。

The upside down Cu2ZnSnSe4 (CZTSe) thin film solar cell device is grown on soda lime glass substrate by plasma-assisted molecular beam epitaxy (PA-MBE). The solar cell uses CZTSe as absorber-layer, cadmium-free buffer layer (ZnSe:Ga), and transparent conducting oxide (TCO) ZnSnO (ZTO). Since the growth temperature of ZTO fit at high temperature for high quality and CZTSe suit at low temperature, the traditional manufacturing process was upside down to avoid broking the absorber properties. The first layer is TCO, and the second is buffer layer and absorber layer, the final is metal back electrode, and all of those are the structure of device. We analyze the solar cell device layer by layer. The ZTO thin films are grown on c-Al2O3 (c-sapphire) and soda lime glass. In X-ray diffraction (XRD) spectra, the crystal structure can be obtained that both of grown on c-sapphire and soda lime glass are amorphous. Additionally, we found that the average roughness of grown on glass was 0.9 nm and c-sapphire was 1.5 nm. According to four-point Hall measurement, the resistivity of ZTO grown on glass is smaller than c-sapphire. With the result, we chose glass as substrate for this solar cell. The lowest resistivity and highest electron concentration of ZnSe:Ga grown on ZTO are1.16 x10-2 Ω-cm and 1.58x1020 (cm-3), respectively.

誌謝 I
摘要 II
Abstract III
目錄 V
List of Figures and Tables VII
CHAPTER 1. Introduction 1
CHAPTER 2. Fundamental properties and Experiment 5
2.1 Crystal structure and material properties of ZnSnO 5
2.2 Crystal structure and material properties of ZnSe:Ga 7
2.3 Experimental apparatus 10
Plasma-assisted molecular beam epitaxy (PA-MBE) 10
Optical spectroscopy 11
2.4 Sample preparation 13
2.5 Sample growth parameters 13
CHAPTER 3. Characterization of CZTSe solar cell 17
3.1 Characterization of ZTO 17
3.2 Characterization of ZnSe:Ga 21
3.3 Analysis of interfaces of CZTSe solar cell 24
CHAPTER 4. Conclusions 27
APPENDIX A. Optical properties of ZnO doped nitrogen 29
Reference 32

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