Title :
Efficiency and Droop Improvement in GaN-Based High-Voltage Light-Emitting Diodes
Author :
Wang, C.H. ; Lin, D.W. ; Lee, C.Y. ; Tsai, M.A. ; Chen, G.L. ; Kuo, H.T. ; Hsu, W.H. ; Kuo, H.C. ; Lu, T.C. ; Wang, S.C. ; Chi, G.C.
Author_Institution :
Dept. of Photonics & Inst. of Electro-Opt. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
The efficiency and electrical characteristics of GaN-based high-voltage light-emitting diodes (HV-LEDs) are investigated in detail. The spatial distribution of light output and simulation results showed that 100-V HV-LED with smaller microchips had superior current spreading. As a result, under 1-W operation, the luminous efficiency of 100-V HV-LED with smaller microchips was enhanced by 7.8% compared to that of 50-V HV-LED, while the efficiency droop behaviors were reduced from 28% in 50-V HV-LED to 25.8% in 100-V HV-LED. Moreover, smaller microchips exhibited lower series resistance and forward voltage, leading to higher wall-plug efficiency.
Keywords :
III-V semiconductors; gallium compounds; light emitting diodes; wide band gap semiconductors; GaN; HV-LED; current spreading; droop improvement; efficiency 28 percent to 25.8 percent; electrical characteristics; high-voltage light-emitting diodes; luminous efficiency; microchips; power 1 W; series resistance; spatial light output distribution; voltage 100 V; voltage 50 V; wall-plug efficiency; Current density; Gallium nitride; Light emitting diodes; Photonics; Proximity effect; Resistance; Simulation; Current spreading; efficiency droop; high voltage; light-emitting diodes;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2153176
