飛秒雷射誘導奈米結構及增加氮化鎵發光二極體之發光功率

Femtosecond Laser Induced Nanostructure and Enhanced Light Output Power of GaN-based Light Emitting Diodes

王思凱(Sih-Kai Wang)

指導教授 ： 李有璋

中原大學/工學院/機械工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000724

摘要

本研究是開發超快雷射誘發週期性表面結構技術，使用1035 nm和517 nm兩種波段之飛秒雷射(Femtosecond Laser)，對發光二極體晶片(Light-Emitting Diodes, LEDs)表面誘發奈米粗糙結構，以破壞發光二極體的內部全反射，提升發光二極體發光效率。有別於目前的LED表面粗化製程，多以乾蝕刻、濕蝕刻和熱退火等方式，飛秒雷射製程相對簡單。雷射誘發週期性表面結構技術是利用超快飛秒雷射的多光子吸收效應與材料發生反應，產生自由電子和金屬膠狀物，雷射進一步激發自由電子後，產生表面電漿，最後依據雷射的偏振方向以電漿耦合的方式作用在金屬膠狀物上，並產生週期性的奈米結構分佈。結果使用光學顯微鏡、掃瞄式電子顯微鏡、原子力顯微鏡、四點探針量測儀、和光激螢光量測儀進行量測，探討奈米結構外觀、電性、RMS表面粗糙度和發光二極體發光強度。薄膜厚度為240 nm之銦錫氧化物薄膜經由1035 nm雷射光源處理，其RMS表面粗糙度由9.161 nm增加至20.562 nm，具有最大結構寬度274 nm；由517 nm雷射光源處理後，最大結構寬度為155 nm。而480 nm膜厚之薄膜經由1035 nm雷射光源處理後具有最大結構寬度366 nm。

關鍵字

發光二極體 ； 飛秒雷射 ； 奈米結構

並列摘要

This study is to use femtosecond laser with wavelength 1035 nm and 517 nm to develop the laser-induced periodical surface structures (LIPSS). LIPSS can be applied to the light-emitting diodes (LEDs) to fabricate nanoroughened surface destroying the total internal reflection (TIR) between semiconductor and free space to enhance the optical efficiency of LEDs. Instead of using the conventional roughened methods of LED including dry, wet etching or annealing process, LIPSS is a relative simple technology which patterns the surface structure via the effect of metallic colloids and surface plasma under plasma coupling mechanism to cause the periodic nanostructure basis on laser polarization.
The surface morphology of this study was investigated by optical microscope (OM), scanning electron microscope (SEM) and atomic force microscopy (AFM). Electrical characteristic was measured by the Four-point probe, and the Photo-Luminescence (PL) is to understand the optical efficiency of LED after laser treatment. Root mean square (RMS) surface roughness of 240 nm thick indium tin oxide (ITO) increases from 9.161 nm to 20.562 nm after 1035 nm wavelength laser treatment. The maximum grain size is 274 nm and 155 nm after 1035 nm and 517 nm wavelength laser treatment respectively. For 480 nm thick ITO, the maximum grain size is 366 nm after 1035 nm wavelength laser irradiation.

並列關鍵字

nanostructures ； LED ； Femtosecond Laser

參考文獻

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