臺灣博碩士論文加值系統

Cu2ZnSn(S,Se)4(CZTSSe)是極具發展潛力的吸收層材料，與現在的CdTe或Cu(In,Ga)(S,Se)2相比，由於鎘為重金屬環境與人體有害，且銦地殼含量稀少且昂貴。而選來與其替換的鋅與錫地殼含量豐富，成本低廉且對環境友善。
研究使用DMSO為溶劑配置溶液，並藉由旋轉塗佈法製備，研究中探討不同鉀離子摻雜濃度對於薄膜的影響，利用SEM、EDS分析硒化後薄膜與成分比例之變化、XRD與Raman確認CZTSSe薄膜之晶體結構，將CZTSSe薄膜製作為元件並透過I-V量測了解其光電特性。
由結果顯示，鉀離子摻雜後，其表面緻密度提高，且結晶邊界缺陷減少，然而隨摻雜濃度增加，底層開始出現孔洞，表面緻密度變差，甚至比未摻雜前產生更多孔洞，隨後再利用不同參雜濃度製作光電元件，其光電轉換效率也與表面形貌有一致性，呈現先上升後下降的情形。在溶液中摻雜一定比例的鉀離子能夠使表面緻密度提高，對元件的表現有相當的幫助，使用此方法所製作之元件效率可達4.94%，開路電壓為0.26V，短路電流密度為48.57mA/cm2，填充因子為40%。
為了將CZTSSe表層(CZTS空乏區寬度只小於100nm)硫化以達到提升開路電壓的同時仍維持短路電流的目的，進一步的實驗採取將硒化後的CZTSSe薄膜再次放入爐管中進行硫化，經由EDS以及XRD分析，我們發現經過不同溫度的再硫化後薄膜中硒的成分將被硫以不同比例所取代，因此可以藉由控制退火溫度以及時間來調整硫與硒之間的比例並且進一步達到控制薄膜的能帶的目的。

SUMMARY
CZTSSe is a promising material for thin film solar cells, which consists of earth-abundant, low-cost and environmentally friendly material compared to CIGS or CdTe. CZTSe thin films were fabricated using DMSO-based spin coating technique. In this work, we investigate the effects of potassium-doping concentration on the selenized CZTSSe thin film. EDS and SEM were performed to analyze the change of composition and morphology of films. XRD and Raman were used to confirm the crystal structure of CZTSSe thin film. CZTSSe-based device was measured through I-V measurement in order to know the photoelectric property.
The result shows that after adding potassium ion, we obtained a denser surface and the grain boundary defects were improved. However as the doping concentration increased the morphology of the film became worse. Holes appeared at the bottom of the film and even more than the film before doping. Then we made devices with different doping concentration and we finally found out that the efficiencies and the morphologies are consistent, which increasing first and then dropping. Thus adding specific amount of potassium is beneficial to the performance of device. The best solar cells showed a conversion efficiency of 4.94%, open-circuit voltage of 0.26V, short-circuit current of 48.57mA/cm2, fill factor of 40%.
To improve the open circuit voltage by sulfurizing the surface of CZTSSe film (The depletion region of CZTS is thinner than 100nm), we put the CZTSSe film into the sulfurization furnace again trying to transfer the surface into CZTS film. By XRD and EDS analyzing, we found out that after different sulfurization temperature annealing, selenium element in the film was replaced by sulfur in different composition. Thus we can achieve our goal of controlling the bandgap of the film by controlling annealing temperature and time.
Keywords: Cu2ZnSn(S ,Se)4(CZTSSe), Solution, Alkali metal doping, Post-sulfurization

目錄
摘要 I
目錄 XIII
圖目錄 XV
表目錄 XVII
第一章 緒論 1
1-1 前言 1
1-2 太陽能電池簡介 2
1-2-1 矽晶太陽能電池 2
1-2-2 薄膜太陽能電池 3
1-2-3 CZTSSe太陽能電池 3
第二章 理論基礎 5
2-1 半導體 5
2-2 PN接面 6
2-3 異質接面 7
2-4 金屬半導體接面 8
2-4-1 蕭特基能障 9
2-4-2 歐姆接觸(Omic contact) 10
2-5 太陽能電池原理 11
2-5-1 太陽輻射(Solar Radiation) 11
2-5-2 操作原理 14
2-5-3 太陽能電池等效電路 16
2-5-4 串聯電阻與並聯電阻的效應 17
2-5-5 太陽能電池的參數 18
2-5-6 太陽能電池量子效率 20
2-6 銅鋅錫硒(CZTSSe)太陽能電池文獻回顧 22
2-6-1 材料特性 22
2-6-2 CZTSSe的晶格缺陷(Defect) 23
2-6-3 元素比例與二次相(Secondary Phase) 24
2-6-4 鹼金屬對CZTSSe吸收層的影響 27
2-6-5 Se含量變化對Cu2ZnSn(S1-xSex)4之影響 27
2-6-6 CZTSSe研究發展與效率較佳的團隊 29
2-7 研究動機 29
第三章 實驗方法 31
3-1 CZTS太陽能電池結構簡介 31
3-2 實驗流程 34
3-2-1 實驗流程架構 34
3-2-2 鉬基板準備與清洗 34
3-2-3 參雜鉀離子銅鋅錫硫前驅物溶液準備與塗佈 35
3-2-4 硒化爐管製成 36
3-2-5 硫化爐管製程 36
3-2-6 去除表層二次相 36
3-2-7 緩衝層CdS製備 37
3-2-8 窗口層製備 37
3-2-9 金屬導電電極製備 38
3-3 儀器介紹 39
3-3-1 高解析掃描式電子顯微鏡(HR-SEM) 39
3-3-2 多功能X光繞射儀 40
3-3-3 拉曼光譜分析 41
3-3-4 太陽光模擬器與IV量測系統 42
第四章 結果與討論 44
4-1 鹼金屬參雜對於CZTSSe薄膜之探討 44
4-1-1 前期研究 44
4-1-2 鹼金屬參雜對於CZTSSe微結構之影響 47
4-1-3 鹼金屬參雜對於元件特性之影響 53
4-1-4 結論 60
4-2 硒化後再硫化對於CZTSSe薄膜之探討 60
4-2-1 純硫化CZTS薄膜微結構與元件特性之前期研究 61
4-2-2 不同溫度再硫化對於CZTSSe微結構之影響 63
4-2-3 硒化後再硫化對於CZTSSe元件效率之影響 68
4-2-4 結論 70
第五章 總結與未來規劃 71
5-1 總結 71
5-2 未來規劃 71

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