以電鍍法成長氧化鋅奈米柱陣列及應用於製成太陽能電池之研究

Abstract

半導體奈米電子、光電、光伏元件等的研究近年來吸引了許多研究工作者的注意。奈米結構具有很高的表面積/體積比，因此比起塊材製造的元件，它在各類的元件上都被期待會有更好的效能。由於奈米柱陣列具有優秀的光捕捉性質，因此使用奈米柱陣列可以用來增加太陽能電池的效率。在眾多奈米材料中，由於氧化鋅奈米柱具有高透光性、高折射係數、材料成本低廉、無毒性、環保等優點，因此是最被廣泛研究的系統。 本論文第一部份首先研究以低溫、低成本的電鍍法成長氧化鋅奈米柱。結果顯示低溫下成長的奈米柱仍然有很好的結晶品質。並且藉由調控成長環境，諸如鋅離子濃度、電鍍電流、成長時間、壓力、溶解氣體等等，可以成長出不同形貌的奈米柱。 在第二部分我們使用低成本的連續離子層吸附反應方法，在室溫下成功地沈積In2S3和CuInS2薄膜於奈米柱基板上。從光學量測上我們得知ZnO/ In2S3/CuInS2核殼奈米柱陣列，對紫外光至近紅外光具有非常好的光吸收性，僅20 nm厚度的CIS殼吸收層，就能將可見光穿透率降至0.15 ％以下。此外，從電性量測結果，我們也發現核殼結構在光電元件上具有值得期待的潛力。

Semiconductor nanostructures have attracted much attention recently because their potential application in making electronic, optoeletronic and photovoltaic devices. Nanostructure has high surface-to-volume ratio which makes it more useful than ordinary devices made of bulk material. In addition the nanorods arrary has very good light-trapping effect and can be used to improve the efficiency of solar cells. Among the many nanomaterials, zinc oxide nanorod has been the most extensively studied one because it is transparent to visible light, has high refractive index, easy to manufacture, non-toxic and friendly to environment. In this study, large-area zinc-oxide nanorods array were grown by electrodeposition. The results show that zinc-oxide nanorods array with good crystalline quality can be obtained at low-temperature. In addition, we also found that ZnO nanorods of different morphologies can be obtained by controlling growth condition such as growth time, pressure, concentration of Zn2+, applied current, dissolved gas, etc. Following the growth of ZnO nanorods, ZnO/In2S3/CuInS2 (CIS) core-shell nanorods array were prepared by successive ionic layer adsorption and reaction (SILAR) method. In the optical measurements, the core-shell CIS nanorods array shows a remarkable absorption from visible to near-infrared light. Only 0.15% of visible light can transmit through a 20nm-thick CIS shell which was grown on the top of ZnO nanorods array. In addition, from photoelectrical measurements, we find that the ZnO/ In2S3/CuInS2 system has the desired probability for making an useful optoelectronic devices.