标题: 具微奈米图案化结构于光电材料应用与光学检测性质之研究
Micro- and Nano-Pattern Structures for Optoelectronic Materials Applications and Research of Optical Inspection Properties
作者: 张哲玮
Chang, Cho-Wei
周长彬
徐瑞坤
Chou, Chang-Ping
Hsu, Ray-Quan
机械工程系所
关键字: 时域有限差分法;次波长结构;微奈米图案化结构;图案化蓝宝石;抗反射;发光二极体;finite difference time domain;sub-wavelength structure;micro-and nano-patterning structure;patten sapphire substrate;anti-reflection;light-emitting diodes
公开日期: 2012
摘要: 本论文采用时域有限差分(finite difference time domain, FDTD)之数值方法分析模拟周期性奈微米结构之光学特性。并且将奈微米周期性图案化结构应用于光学膜面之塑胶基材表面以奈米压印方式制作两种不同形态之3D次波长结构,并检验其光学性质。于奈米光学模拟研究中发现,结构采尖锥或蛾眼圆锥形状,当高宽比≥0.6时,在波长250nm~800nm范围内其反射率均小于1%。实际之结构制作系于PMMA及PET等塑胶材料表面以热压印及紫外光固化成型结构。经过验证实作结构之光学性质与FDTD数值模拟结果相当一致。
而另一项研究是提出一种创新的思维方法,开发出一种新型的”金属嵌入式光罩制程技术”并应用于光电材料的蓝宝石基板上制作光阻结构,再经由干式蚀刻产生可应用于高亮度发光二极体 (light emitting diode, LED) 的图案化蓝宝石基板,此一新型光罩的特点是,除了具有一般模仁表面的凹、凸结构外,其微结构的部份表面 (例如结构凸起面、或结构凹下面) 会覆盖一金属层,可以阻挡 UV光的穿透。另外,此一光罩的材质为PDMS,为一可挠性甚佳的材质,可以迁就蓝宝石基板的翘曲或不平整表面,达到全面紧密贴合的要求。利用PDMS软模光罩成功于2寸蓝宝石基板上制作线宽1 µm、周期2 µm 及光阻柱高度为1.4 µm 的六角最密堆积排列的结构。另外,透过LED基板磊晶与元件制作后,利用脉冲雷射蚀刻制作周期性微/奈米结构在发光二极体之透明导电层(transparent conducting oxide, TCO)表面,藉此破坏内部全反射以提升发光二极体之光萃取效率,实验结果显示可增进LED出光效率高达16%。
The development of coating technique to lower the reflected light and increase the optical efficiency of an optical system is a very important topic for modern optical elements. Recently, the use of anti-reflection (AR) structured surface has been proposed as an applicable alternative based on both the theoretical and the experimental study. In this article, antireflection structured surface was analyzed by the finite difference time domain (FDTD) method in the visible light spectrum and has been successfully fabricated on plastic substrate by nano-imprint process. The FDTD numerical calculation was used to analyze the AR structured surface by the designed profile 3-D pyramid and conical structure. Both of the structures showed the antireflection (AR) effect (reflectance<1%) when the aspect ratio of the 3D structure was larger than 0.8. In the nano-imprint process, hot embossing and UV curing process were applied to generate 3D nano-structure on plastic substrate as PMMA and PET. The optical property of the fabricated polymer film showed good agreement with the simulation result.
In another work, we proposed a new type of metal embedded soft photo-mask based on a PMDS mold. Due to its compliance, this new soft photo-mask can from intimate contact with a slight-curved sapphire wafer and carry out UV exposure in photolithography and therefore forming PR microstructures on a sapphire substrate. During the exposure process, part of incident light is selectively blocked from metal film and others are guided by the convex PDMS structures and onto the photo-resist layer. For the soft PDMS photo-mask, hexagonal arrays of PR micro-pillars with a diameter around 1 µm and a height of 1.4 µm are successfully created on a 2 inch sapphire substrate. Subsequently, the pattern sapphire substrates (PSS) for LEDs can be readily obtained by applying ICP etching on this PR-patterned sapphire substrate. In addition, pulsed lasers were used to fabricate micro/nano structures on the transparent conducting oxide (TCO) layers of the light emitting diodes (LEDs) with pattern sapphire substrate to destroy the total internal reflectionat TCO/air and enhance the light extraction efficiency. It can improve LED light extraction efficiency up to 16%.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079614801
http://hdl.handle.net/11536/72459
显示于类别:Thesis