條紋式半極化(1-101)氮化鎵/氮化銦鎵藍光發光二極體特性研究; Characterization of Multi-stripes Semi-polar(1-101) GaN/InGaN Light Emitting Diodes

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Title:	條紋式半極化(1-101)氮化鎵/氮化銦鎵藍光發光二極體特性研究;Characterization of Multi-stripes Semi-polar(1-101) GaN/InGaN Light Emitting Diodes
Authors:	賴柏辰;Lai,Po-Chen
Contributors:	電機工程學系
Keywords:	半極化;(1-101);氮化鎵;發光二極體;semi-polar;(1-101);GaN;Light Emitting Diode
Date:	2013-11-08
Issue Date:	2014-02-13 17:52:19 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究中係在矽基板上製作V型凹槽並成長具有半極化(1-101)面的氮化鎵/氮化銦鎵發光二極體結構，將其製作成元件。因為具有半極化(1-101)面的量子井發光二極體結構具有較小的反向極化電場，模擬分析以及量測結果顯示，此結構能夠改善效率衰退(Efficiency droop)的問題，與一般極化(0001) 發光二極體比較，前者之效率衰退的比例僅有11.52 %，而後者則高達52.1 %。然而長條紋島狀結構容易在接合處引發非(1-101)的傾斜晶格面，產生大量的錯誤堆疊以及缺陷，使得在接合處的銦分布不均勻，造成發光不均勻和強度下降。為了將發光效率提高以及改善發光純度問題，本研究提出了一種新結構的設計，於傾斜7°(001)矽圖形化基板上成長半極化(1-101)氮化鎵材料時，不讓最初的氮化鎵條紋島狀結構接合，而是在條紋島上成長為具有多層量子井的獨立長條紋島狀發光二極體結構。此新結構不僅免除了長條紋島狀結構因接合產生的應力而龜裂，和傳統接合式的半極化發光二極體相比，PL的半高寬從44.3 nm降到35.9 nm，最重要的是大幅提升了1x1 mm2的元件在350 mA下的發光強度達66.7 %，使得半極化(1-101)發光二極體有了更好的光電特性。此方法不僅改善了效率衰退的問題，更提升了自身的光電特性，提供一個發光二極體未來發展的方向。 In this thesis, semi-polar (1-101) GaN / InGaN LEDs was fabricated on v-groove Si (001) substrates and processed to devices. Semi-polar (1-101) plane GaN can improve efficiency droop due to the weak reverse polarization field which can be observed by simulation tools. The efficiency droop ratios of polar and semi-polar LEDs are 52.1% and 11.52% respectively. However the amount of inclination was increased at higher indium content. Inclining is caused by the vest of existence of stacking faults or defects at InGaN/GaN interface on the coalescence region. Therefore, this inclination will affect the In fluctuation and decrease the light output power. In order to improve the light emission efficiency and purity problems, this study proposes a new structural design. It is called multi-stripes structure, consists of n-GaN layer without coalescence, an active region composed of InGaN/GaN quantum well cover the triangle surface, and p-GaN layer make coalescence layer of each stripe. This new structure not only eliminates cracking caused by stress, but also has a great improvement compares with coalescence structure. The photoluminescence shows FWHM dropped from 44.3 nm 35.9 nm and the output power enhanced up to 66.7% (1x1 mm2 device at 350 mA). It shows semi-polar (1-101) light-emitting diodes have a better optical property. This study proposes a new structure - "multi-stripe semi-polar (1-101) GaN light-emitting diodes." The new structure not only improves the efficiency droop problem but also enhances the optical characteristics, which provides a modern direction of LEDs development.
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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