以電鍍法製備CIGS太陽能電池之吸收層

Electrodeposition of CIGS Solar Cell Absorber

韓弼任(Pi-Jen Han)

指導教授 ： 謝淑惠

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2010年)

https://doi.org/10.6827/NFU.2010.00049

摘要

銅銦鎵硒[Cu(In, Ga)Se2，CIGS]是ㄧ薄膜型的太陽能電池，其吸收層屬於P型半導體材料，其能隙介於1.04~1.68eV之間，具有高吸收和高轉換效率，適合取代傳統的矽晶太陽能電池，以解決矽礦原料的不足和降低用料與廢料。一般CIGS吸收層皆以真空製程製作，如:濺鍍、蒸鍍或化學氣相沈積等，其沈積的薄膜較緻密、物理性質和電性較好，且良率和再現性高，但其設備和製作成本過高、產率較低，不符合低成本的太陽能電池。
本研究以電鍍法取代真空系統，電鍍浴中含有所需金屬離子，以Pt作為相對電極，藉由改變鍍浴的pH值、沉積電壓與沉積時間，在Mo基材上沉積Cu-InCu-Ga和Cu-GaCu-In雙層結構的前驅層，再經由初步的熱處理與硒化製程，以掃描式電子顯微鏡(SEM)、X光能量分散光譜儀(EDS)、X光繞射光譜儀(XRD)分析與電化學量測，比較不同組合的微觀結構、界面結合性、薄膜成份、組成結構與薄膜類型。
實驗結果發現，沉積條件為：Cu-In電鍍浴在pH 3、沉積電壓 - 5.5 V 、沉積時間15 秒；與Cu-Ga電鍍浴在pH 2.65、沉積電壓 - 2.45 V、沉積時間55 秒，所沉積的 Cu-InCu-Ga疊層的表面顆粒分佈較均勻，是比較理想的疊層方式，經由熱處理與硒化製程硒化Cu-InCu-Ga疊層，以XRD分析硒化前後的薄膜結構，證實電鍍法沉積Cu-InCu-Ga雙層結構的CIG前驅層，再經過熱處理與硒化製程，Cu-InCu-Ga雙層薄膜會轉變成CIGS薄膜，晶體結構也轉變成CuGa0.3In0.7Se2的黃銅礦結構。

關鍵字

CIGS ； 電鍍法 ； Cu-In ； Cu-Ga

並列摘要

Cu(In, Ge)Se2 is a thin film solar cell and its absorber is a P type semiconductor with energy gap between 1.04 - 1.68 eV. It is suitable for replacing the traditional Si solar cell due to its high absorbent coefficient and high conversion efficiency. There are many methods such as physical vapor deposition (PVD), sputtering, chemical bath method (CBD) etc. for growing CIGS absorber and in general vacuum method is the most used procedure which could deposit dense films with better physical and electrical properties. It is well known that vacuum method needs expensive vacuum equipment or expensive target. The process for vacuum method is also quite complicated. To improve these shortages of typical CIGS absorber stated above, the present study used electroplating method to replace vacuum method.
In this study, bimetal layers have been electroplated on Mo surface with Pt working electrode, which are structure of Cu-InCu-Ga and Cu-GaCu-In precursor. Before electroplating, Mo film was sputtered on Si substrate. And then the individual precursor films and the annealed films were observed by scanning electron microscope, energy dispersive X-ray spectrometry, X-ray diffraction, and electrochemical measurement.
Experimental results show that the Cu-InCu-Ga film is more dense and uniform than Cu-GaCu-In, after annealed at Ar atmosphere for 20 minutes, which is composed of Cu, In and Ga at the ratio of 1:0.69:0.69 and the interface between Cu-GaCu-In is in well adhesion. The result could complete CIGS absorber after selenization of the Cu-InCu-Ga precursor film.

並列關鍵字

CIGS ； Electrodeposition ； Cu-In ； Cu-Ga.

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