- 學位論文
以金屬有機化學氣相沉積法應用表面活性劑銻於磷化銦鎵/砷化銦鎵/鍺三接面變質太陽能電池
Applied surfactant Sb in GaInP of metamorphic Ge/InGaAs/GaInP triple-junction solar cells by MOCVD
摘要
本文研究內容係透過低壓有機金屬氣相沉積法，於磷化銦鎵磊晶層生長過程中添加表面活化劑三甲基銻，搭配具有晶格不匹配之砷化銦鎵形變緩衝層作為虛擬基板，試圖於形變緩衝層上方成長具有高能隙的磷化銦鎵磊晶層。於晶格不匹配之樣品(S1)觀察到的效應，包含雜質二乙基鋅摻雜過程的延遲效應、表面存有顆粒狀的缺陷、由磷化銦組成之反相邊界缺陷及磷間隙缺陷的存在，在光學量測結果顯示樣品表現出微弱之近能隙光激發螢光強度、並擁有1~2 ns等級的快速少數載子(電子)生命期等結果。 在晶格不匹配之磷化銦鎵磊晶層的成長過程添加表面活化劑三甲基銻，觀察到樣品S2、S3呈現台階匯聚的情況、表面三角凸出物的分佈密度降低，而且使用表面活化劑也並不明顯影響磊晶速率。表面活化劑三甲基銻具有降低三族原子置換能的動力學機制，這項機制使得表面活化劑得以抑制摻雜的延遲效應並表現出自由載子(電洞)濃度提升等現象。另一方面，透過拉曼、光激發螢光、時間解析等量測系統，觀察到磷化銦組成之反相邊界缺陷的抑制成效，同時樣品(S2)也表現出強烈的光激發螢光強度，與長達57 ns的少數載子(電子)生命期。再者，使用表面活化劑在三接面太陽能電池的磷化銦鎵子電池層中，在低聚光(AM1.5G，1太陽數)條件下，在1/4片4吋晶片上切割的晶元之間，展現出均勻的開路電壓分佈情況，並在AM1.5G、110個太陽數量測條件之下，觀察到具有優異的的短路電流密度。表面活化劑使太陽能電池擁有較小串聯電阻、較大的並聯電阻與轉換效率等優異電學特性參數的展現。
並列摘要
In this thesis, we studied the lattice-mismatch GaInP epilayers with surfactant antimony (Sb), which were grown on metamorphic (MM)-InGaAs buffer layers by low pressure metal organic chemical vapor deposition (MOCVD). The target is to obtain the GaInP epilayers with large energy band gap on the MM-InGaAs buffer layers. The experimental results show that the CuPt ordering in GaInP epilayers was diminished by the introduction of surfactant Sb during the growth. Furthermore, the surface roughness, the lagging effect of Zn-doping and the InP-chain anti-phase boundaries (APBs) were significantly improved by adding the surfactant Sb. Moreover, the GaInP/MM-GaInAs/Ge multi-junction solar cells made by this method exhibit the enhanced short circuit current density and a narrower distribution of the open circuit voltage. We believe the use of surfactant Sb to improve the APBs during the growth of InGaP would be very useful for designing GaInP-based solar cells.