奈米結構薄膜之製備與光電元件應用

近年來光電元件效率提升愈來愈重要，除了在新材料的研發上努力之外，引進具有奈米結構的薄膜實為另一有效的方向。具有奈米結構的薄膜因在光電特性上具有可調性，近年來已有廣泛的應用。此薄膜因可以隨著製程方法來控制其光電特性及幾何結構形貌，所以可以在光電元件中加入奈米結構薄膜，改善原本元件的結構，用以增加元件效率。本文首先探討利用有表面紋理結構的氟摻雜氧化錫透明導電基板鍍上白金，作為染料敏化太陽能電池的對電極，而因為表面具有紋理結構的基板有程度不一的表面起伏特性，在鍍上白金後可以藉由表面接觸面積的增加來增加與電解質的反應，有效的提升染料敏化太陽電池的元件效率。本文接著使用斜角蒸鍍法來製作奈米結構薄膜，斜角蒸鍍法是利用原子在沉積過程中蒸鍍源和基板有傾斜角的情況製作而成。此種薄膜可以依據不同的成長條件，而且有不同的光電特性及幾何結構，而可以彈性的應用在光電元件上。本文使用斜角蒸鍍技術來製作染料敏化太陽能電池所需的白金對電極。利用在大入射角的條件製作具有較高孔隙率的白金對電極，也是利用表面接觸面積的增加來有效增加元件效率。最後我們利用斜角蒸鍍技術製作氧化銦鍚薄膜；在不同的入射角條件下，氧化銦錫薄膜會有不同的光電特性，如：折射率、穿透率及片電阻。最後本文則對斜角蒸鍍薄膜在不同的退火條件下所擁有的光電特性進行分析，找出退火溫度和時間對薄膜特性的影響。提供了日後光電元件應用之基礎。

關鍵字

奈米結構薄膜；紋理結構；白金對電極；染料敏化太陽能電池；斜角蒸鍍法；氧化銦鍚

並列摘要

In recent years, the improvement of efficiency of optoelectronic devices has become more and more important. As such, the nano-structured thin films can greatly benefit device efficiency. The nanostructured thin films could have tunable optical and electrical properties and already have wide applications in optoelectronics. In this thesis, first we used the fluorine-doped tin oxide (FTO) with different texture structures to fabricate nanotextured Pt counter electrodes of dye-sensitized solar cells (DSSCs). With different surface roughnesses in textured FTO substrates, the reactive surface areas between the electrolytes and the platinum counter electrodes were increased to improve the efficiencies of DSSCs Next, we studied the glancing angle deposition (GALD) for fabrication of nanostructured thin films. The GLAD technique makes use of oblique-angle deposition from the evaporation source to the substrate. Tunable optical and electrical properties and morphologies could be obtained by different fabrication conditions and their applications on optoelectronic are promising. First, we fabricated the platinum counter electrodes by GLAD for DSSCs. The highly porous platinum counter electrodes prepared by large deposition angles can effectively enhance active surface areas to improve the DSSC efficiency. Then, the indium tin oxide thin (ITO) film was fabricated by GLAD. The optical and electrical properties of the GLAD ITO were varied with different deposition angles, such as the refractive index, transmission and sheet resistance. We also investigated the optical and electrical properties of GLAD ITO with different annealing conditions, including anneal temperature and annealing time. Results of this study shall provide the guideline for future applications of GLAD ITO to optoelectronic devices.

並列關鍵字

nano-structured thin film ； texture structure ； platinum counter electrode ； dye-sensitized solar cells ； glancing angle deposition ； indium tin oxide

參考文獻

1]S. R. Kennedy, "Photonics Applications of Nanostructured Thin Films," Department of Electrical and Computer Engineering, University of Alberta, 2004.