相較於傳統燈泡，發光二極體(Light Emitting Diode, LED)具有省電、環保等優勢，故有綠色照明之稱。目前對於發光二極體的研究，主要著重於改善光萃取效率及提升散熱能力及白光發光二極體的實現等，而本研究將利用次微米光柵結構來改善光萃取效率並且對於發光二極體的光型調制作探討。在本文中先以模擬分析發光二極體結構，接著針對如何製作不同外型及結構參數的次微米光柵應用於氮化鎵發光二極體上做深入討論，並以螢光激發量測其光萃取效率說明次微米光柵在發光二極體上之應用。製程方面以電子束微影及乾蝕刻的方式，來製作次微米光柵，藉由不同尺寸規格的次微米光柵來探討結構的變異對於光萃取效率以及光型調製的影響。經由模擬及量測結果，次微米光柵可以破壞氮化鎵結構內的光波導模態(waveguide mode)，使結構內部的光經由次微米光柵萃取出來。對於結構外型趨於梯形或是三角形的次微米光柵，在斜邊部分增加了出光面積，提升了光萃取量，相對也改善了光萃取效率。 次微米光柵改變發光二極體在空間中的光強分佈，使得原本的朗伯分佈(lambertian distribution)光型被調制為光強均勻分佈在正負50度角內的光型圖樣。藉由次微米光柵來使得發光二極體光型趨於均勻的理念，可應用於LCD的背光板上，改善發光二極體光源的均勻性。The looks, relatively in the traditional bulb, LED (Light Emitting Diode) has province electricity, environmental protection advantage, have claiming green to light. To the research of LED at present, mainly focus on improving light extracting efficiency and improving the ability of heat dissipation and white light LED realization. This research will be use sub-micro grating structure to improve light extract efficiency and modulate light pattern of LED. In this thesis, first to analyze of LED structure by simulation, and treat to how make sub-micro grating of different structure profile and different structure parameter on GaN-LED. Measurement light extraction efficiency by using PL (photoluminescence) to explain application of sub-micro grating on LED. To fabrication sub-micro grating by using E-beam lithography and dry etching, and using different dimension of sub-micro grating to discuss the influence of light extraction efficiency and light pattern. By simulation and measurement result, sub-micro grating can destroy waveguide mode of GaN epitaxy structure, let light extract from inside of structure. The structure of profile to trapezium or triangle of sub-micro grating can to increase light extract area from the bevel. The amount of light extraction and improve light extraction efficiency of LED advanced by the bevel structure. Sub-micro grating changed light intensity distribution in airspace of LED. Let light pattern of lambertian distribution of LED modulated the uniform light pattern in within ±50 degree. We can use the notion that light pattern be uniform by sub-micro gratings. To appliance on back light of LED can improve the light source of LED be uniform.
