Browsing by Author "Yen, Sheng-Horng"

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Experimental and theoretical analysis on ultraviolet 370 nm AlGaInN light-emitting diodes
(2006-05-01)
Chang, Yi-An
;
Yen, Sheng-Horng
;
Wang, Te-Chung
;
Kuo, Hao-Chung
;
Kuo, Yen-Kuang
An ultraviolet (UV) AlGaInN light-emitting diode (LED) with 370 nm emission is demonstrated. At room temperature (RT) UV power of 0.8 mW at 20 mA with 3.6 V operation voltage is achieved. It provides 4 mW output when driven at 125 mA under continuous-wave (CW) operation. Qualitative optimization of the Al composition in the AlGaN electron-block layer and the quaternary AlGaInN quantum well (QW) number of the UV LED is also investigated in this study. The numerical results fit with the experimentally demonstrated output performance of our AlGaInN UV LED. We find that the UV AlGaInN LED can provide better output characteristics when the Al composition in the AlGaN electron-block layer is in the range 19-21 % and the AlGaInN QW number is in the range 5-7 by reducing the electron leakage current.
Improvement in output power of a 460 nm InGaN light-emitting diode using staggered quantum well
(2010-09-15)
Liao, Chih-Teng
;
Tsai, Miao-Chan
;
Liou, Bo-Ting
;
Yen, Sheng-Horng
;
Kuo, Yen-Kuang
Staggered quantum well structures are studied to eliminate the influence of polarization-induced electrostatic field upon the optical performance of blue InGaN light-emitting diodes (LEDs). Blue InGaN LEDs with various staggered quantum wells which vary in their indium compositions and quantum well width are theoretically studied and compared by using the APSYS simulation program. According to the simulation results, the best optical characteristic is obtained when the staggered quantum well is designed as In(0.20)Ga(0.80)N (1.4 nm)-In(0.26)Ga(0.74)N (1.6 nm) for blue LEDs. Superiority of this novelty design is on the strength of its enhanced overlap of electron and hole wave functions, uniform distribution of holes, and suppressed electron leakage in the LED device. (C) 2010 American Institute of Physics. [doi:10.1063/1.3471804]