本文選題：垂直結(jié)構(gòu)LED芯片 + 出光效率��； 參考：《華南理工大學(xué)》2016年碩士論文

【摘要】：GaN基垂直結(jié)構(gòu)LED芯片相對(duì)傳統(tǒng)結(jié)構(gòu)LED芯片具有出光面積大,散熱性能好,電流擴(kuò)展均勻等優(yōu)點(diǎn),更加適用于大功率固態(tài)照明光源,是LED照明發(fā)展的一個(gè)重要方向。然而垂直結(jié)構(gòu)LED芯片的制備工藝更加復(fù)雜,本文在完善垂直結(jié)構(gòu)LED芯片制備工藝的同時(shí),對(duì)垂直結(jié)構(gòu)LED芯片的結(jié)構(gòu)進(jìn)行設(shè)計(jì),對(duì)芯片出光面N極性的氮化鎵層表面結(jié)構(gòu)進(jìn)行研究,對(duì)垂直結(jié)構(gòu)LED芯片的表面n型電極結(jié)構(gòu)進(jìn)行優(yōu)化,最終獲得高效大功率的垂直結(jié)構(gòu)LED芯片。針對(duì)光在空氣/n-GaN界面處的菲涅爾反射、全反射引起光子損耗,從而限制垂直結(jié)構(gòu)LED芯片出光效率的問題,利用N極性面Ga N出光面易被KOH溶液刻蝕而改變表面結(jié)構(gòu)的特點(diǎn),以KOH溶液為刻蝕液,分別對(duì)普通表面GaN基垂直結(jié)構(gòu)LED芯片和具有表面周期性微結(jié)構(gòu)的芯片進(jìn)行N極性面GaN的表面結(jié)構(gòu)優(yōu)化研究。在刻蝕普通表面N極性面GaN的過程中,當(dāng)刻蝕濃度為6mol/L,刻蝕溫度為80℃,刻蝕時(shí)間為8min時(shí),樣品光輸出功率與參考樣品相比提升了175%@100mA;而在具有表面周期性微結(jié)構(gòu)的N極性面GaN表面結(jié)構(gòu)刻蝕優(yōu)化過程中,采用刻蝕溶液的濃度為2mol/L,溫度為95℃,刻蝕的時(shí)間為6min的條件獲得了較優(yōu)的刻蝕效果,此時(shí)樣品光輸出功率與參考樣品相比高出23.08%@100mA。針對(duì)大電流注入下電流易在n電極下方集聚的問題,利用電流路徑模型分析n型電極尺寸及間距等對(duì)垂直結(jié)構(gòu)LED芯片電流分布均勻性的影響,依此設(shè)計(jì)出一種螺旋狀環(huán)形結(jié)構(gòu)電極。通過建立有限元分析軟件COMSOL Multiphysics仿真模型模擬垂直結(jié)構(gòu)LED芯片有源層的電流密度分布,發(fā)現(xiàn)螺旋狀環(huán)形結(jié)構(gòu)電極的環(huán)間距越小,電流密度分布越均勻。利用垂直結(jié)構(gòu)LED芯片制備技術(shù)實(shí)現(xiàn)具有螺旋狀環(huán)形電極的垂直結(jié)構(gòu)LED芯片。實(shí)驗(yàn)結(jié)果顯示,在350mA電流注入下,當(dāng)電極環(huán)間距為146.25μm時(shí)的芯片具有最大的功能轉(zhuǎn)換效率,達(dá)到26.8%。
[Abstract]:Compared with the traditional LED chip, GaN based vertical structure LED chip has many advantages, such as large light area, good heat dissipation, uniform current spread and so on. It is more suitable for high power solid-state lighting source. It is an important direction in the development of LED lighting.However, the fabrication process of vertical structure LED chip is more complicated. In this paper, the structure of vertical structure LED chip is designed while perfecting the fabrication process of vertical structure LED chip.The surface structure of gallium nitride layer with N polarity is studied, and the surface n-type electrode structure of vertical structure LED chip is optimized. Finally, a high efficiency and high power vertical structure LED chip is obtained.Aiming at the Fresnel reflection of light at the air / n-GaN interface, the total reflection causes photon loss, which limits the optical efficiency of the vertical structure LED chip. The characteristic of changing the surface structure by using the N polarity surface Ga N luminous surface is easy to be etched by KOH solution.Using KOH solution as etching solution, the surface structure optimization of normal surface GaN based LED chips and chips with periodic surface microstructures was studied respectively.When the etching concentration is 6 mol / L, the etching temperature is 80 鈩，

本文編號(hào)：1765217