Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/10160
標題: Analyzed the Optoelectronic Property with a Patterned GaN Epitaxial Layer
探討圖案化氮化鎵對元件發光特性之影響
作者: Hsieh, Tsung-Han
謝宗翰
關鍵字: GaN
氮化鎵
Patterned
Light emitting diode
圖案化
發光二極體
出版社: 材料科學與工程學系所
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摘要: 本論文中,利用雷射處理與化學濕式蝕刻技術,製作具有背面粗化增加光取出效率的發光二極體元件,經由雷射處理與濕式蝕刻後,在氮化鎵(GaN)與藍寶石基板(Sapphire)介面間產生空孔與{10-1-1}面倒立六角錐結構(Hexagonal inverted pyramid structure, HIP),將對此結構之發光二極體元件電性與光性加以探討。本實驗將探討條紋圖案化氮化鎵模板重新成長發光二極體結構之元件(Laser treatment re-growth light emitting diode, LTRG-LED)與區域性圖案化氮化鎵發光元件(Bridge light emitting diode, Bridge-LED)兩者相對於傳統發光二極體(Standard LED, ST-LED)特性研究,將分別研究兩種圖案化氮化鎵發光元件對發光特性之影響。 實驗一,LTRG-LED使用具條紋圖案化空孔與倒立六角錐結構氮化鎵模板重新成長發光二極體結構,製作出條紋圖案化發光元件,重新成長過程中因為條紋圖案化的空孔結構,造成磊晶成長的溫度產生不均勻現象,因為空氣(0.023 W/m•k)的熱傳導比氮化鎵(1.3 w/m•k)小,週期性空孔結構使發光層銦含量的析出與波長產生週期性變化,具背後粗化的發光元件光取出效率相較於ST-LED有107%的提升,在LTRG-LED元件中觀察到波長紅移、較低的壓電場與內部量子效率提升的效應產生。 實驗二,Bridge-LED結構的製作是利用正面雷射切割、背面雷射處理與化學濕式蝕刻,製作出區域性圖案化氮化鎵發光元件,在不影響InGaN發光層之下,製作具51%粗化面積的圖案化元件,光取出效率相較於ST-LED有103%提升,發散角變小是因為氮化鎵與藍寶石基板介面間具有倒立六角錐結構,使光趨於軸向,電激發波長不變,但在大電流下半高寬有變大的趨勢,100mA操作電流下外部量子效率之衰退效率無明顯差異,製作出高取光區域性圖案化氮化鎵發光元件。 利用雷射處理與化學濕式蝕刻技術,在氮化鎵與藍寶石基板介面間產生空孔與倒立六角錐結構,利用兩種不同製程,製作高取光效率發光二極體,應用於高效率的發光元件當中。
The InGaN-based light emitting diodes (LEDs) with a roughened patterned backside on the N-face GaN surface were fabricated through a chemical wet etching process to increase light extraction efficiency. After laser treatment and the chemical wet etching process, the air-void structure with a stable chemical crystallographic {10-1-1} plane was formed at the GaN/Al2O3 interface. In this study, we analyzed optical and electrical of these two kinds of LEDs, the laser treatment re-growth light emitting diode (LTRG-LED) and bridge light emitting diode (Bridge-LED), compared to the standard LED (ST-LED). In the first experiment, the n-GaN template with a stripe patterned air void structure and a hexagonal inverted pyramid (HIP) structure was used to re-grown LED structure. At the re-grown process, the growth temperature was distributed non-uniform on the GaN template layer with the strip-shaped air void structure. Because the thermal conductivity of the air void (0.023 W/m•k) is smaller than the GaN material (1.3 W/m•k). The indium content and the emission wavelength in the quantum well was periodic distributed corresponded to the stripe patterned air void structure. The light output power of the LED chip with the backside roughened surface had a 107% enhancement compared with the ST-LED chip. The EL wavelength redshifted, the lower piezoelectric field and the high internal quantum efficiency were observed in the LTRG-LED structure. In the second experiment, the Bridge-LED structure was fabricated through a laser scribing, a laser treatment and a chemical wet etching process that the InGaN active layer was not damaged in the process. The light output power of the LED with a 51% backside roughened area had a 103% enhancement compared with the ST-LED. The divergent angle became small that was caused by forming the inverted pyramid shaped structures on the roughened patterned backside at the GaN/Al2O3 interface. The EL emission wavelength of both LED structures was almost the same, but the EL line-width of the treated LED structure became broadened at high injection current. A similar efficiency droop effect (about 70%) was observed for both LED structures at 100mA operating current. The air void and the HIP structure at the GaN/Al2O3 interface were fabricated through these two kinds of processes on the GaN LED structures to enhance light extraction efficiency for the high efficiency nitride-based LED applications.
URI: http://hdl.handle.net/11455/10160
其他識別: U0005-1507201117484800
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