Title :
Efficiency Enhancement of InGaN LEDs With an n-Type AlGaN/GaN/InGaN Current Spreading Layer
Author :
Hsueh-Hsing Liu ; Peng-Ren Chen ; Geng-Yen Lee ; Jen-Inn Chyi
Author_Institution :
Dept. of Electr. Eng., Nat. Central Univ., Jhongli, Taiwan
Abstract :
This letter reports an InGaN light-emitting diode (LED) structure that has an n-type Al0.1Ga0.9N/GaN/In0.06Ga0.94N current spreading layer under its multiple-quantum-well active region. As indicated by simulation, the Al0.1Ga0.9N/GaN/In0.06Ga0.94 N heterostructure induces a higher electron concentration than an n-AlGaN/GaN cladding layer and an n-GaN/InGaN current spreading layer that are used in conventional LEDs. As a result, the proposed n-type spreading layer is expected to alleviate current crowding and improve external quantum efficiency. Experimentally, the light output uniformity across the chips is greatly improved. The output power and wall-plug efficiency are enhanced by about 18.2% and 22.2% at an injection current of 350 mA for the LEDs employing the new double-heterostructure current spreading layer.
Keywords :
III-V semiconductors; aluminium compounds; gallium compounds; indium compounds; light emitting diodes; quantum well devices; semiconductor device models; wide band gap semiconductors; AlGaN-GaN-InGaN; InGaN; LED; current 350 mA; efficiency 18.2 percent; efficiency 22.2 percent; electron concentration; light-emitting diode; multiple-quantum-well active region; n-type current spreading layer; quantum efficiency; wall-plug efficiency; Aluminum gallium nitride; Current measurement; Gallium nitride; Light emitting diodes; Power generation; Proximity effect; Resistance; GaN; InGaN; light-emitting diodes (LEDs);
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2163490
