銅銦硒化物之奈米、微米結構應用於太陽能電池之製備與分析

I-III-IV2族半導體(例如CuInSe2、CuInGaSe2)由於其優異的光學吸收特性為目前極具前景的薄膜太陽能電池材料；另一方面由於奈米結構陣列具有獨特的光學吸收特性，已有許多奈米結構製程技術被提出，因此在本論文第一部分我們提出新穎非真空製程技術製作CuInSe2奈米柱陣列並探討其光學特性並應用於太陽能電池，奈米柱陣列以CuInSe2奈米粒子作為前驅物，並藉由機械式刮刀法填入陽極氧化鋁模板內，XRD和Raman光譜顯示CuInSe2奈米柱成功生成於陽極氧化鋁模板內，在陽極氧化鋁模板移除後可得到垂直排列的CuInSe2奈米柱陣列，由TEM分析可看出CuInSe2奈米柱為多晶結構，由UV-Vis光譜分析發現CuInSe2奈米柱具有1.2%反射率低於9.8%的原始反射率，反射率降低可由漸變式的折射率梯度解釋，而由吸收率切線截距測得能隙約1.01 eV與CuInSe2塊材相符，整體而言此機械式刮刀法具有簡單且低成本之製程優勢。第二部分我們利用氮化矽奈米尖錐陣列製作CuInGaSe2奈米反釋迦結構陣列，並研究其光學特性進而製成太陽能電池元件。氮化矽奈米尖錐陣列由ICP-RIE製程製備而得，Mo背電極與CIGS吸收層由濺鍍法製備，CuInGaSe2吸收層厚度調變範圍為0.5-2 µm，隨厚度增加可看出反釋迦結構陣列由獨立分離漸漸轉為彼此互相重疊，藉由XRD光譜可看出CIGS奈米反釋迦結構陣列為黃銅礦結構，UV-vis光譜分析發現CIGS奈米反釋迦結構陣列反射率大幅降低且0.5 µm的元件具有最高的短路電流，目前元件最高效率為0.9%。

關鍵字

CIS ；奈米結構；微結構；太陽能電池；週期性結構

並列摘要

The compounds of I-III-IV2 group elements have attracted much attention in recent years because of their unique electronic and optical properties. CuInSe2 (CIS)-based solar cells, due to the thinner absorber layer about the thickness of 2 µm, is very promising renewable PV. Due to the outstanding optical properties of nanostructures, researchers have developed many techniques to create different nanostructures for solar cell devices, In this thesis, we have introduced a novel non-vacuum technique for the fabrication of CuInSe2 NRs and studied its optical properties for applications in solar cell. Further, we have fabricated CuInGaSe2 (CIGS) inverted micro sugar apple (IMSA) array structure, studied its optical properties and fabricated the device structure. In the first part, low cost and vacuum free method for fabrication of vertically aligned copper indium diselenide (CuInSe2) nanorod (NR) arrays from pre-synthesized CuInSe2 nanoparticles (NPs) by mechanical approach using porous anodic alumina oxide (AAO) as a template was demonstrated. This approach utilized a rubbing technique to fill CuInSe2 NPs into AAO template. X-ray diffraction and Raman spectroscopy study was employed to confirm the phase of CuInSe2 NPs before and after formation of NRs. Vertically aligned CuInSe2 NR arrays were obtained after removal of AAO template. The polycrystallinity and composition of NR was confirmed by transmission electron microscope. Optical study of CuInSe2 NPs film revealed a reflectance of ~9.8 %, while a significant reduction of the reflectance to ~1.2 % was observed after the formation of CuInSe2 NR arrays. The observed low reflectance behavior is attributed to a concept of gradual refractive index with vertical array structures. Band gap of CuInSe2 NRs was observed to be ~1.01 eV from differential reflectance spectra, which is identical to its bulk value. This template-assisted mechanical approach of vertically aligned NR arrays is simple and inexpensive.