Title :
Tandem Structure for Efficiency Improvement in GaN Based Light-Emitting Diodes
Author :
Miao-Chan Tsai ; Leung, Bosco ; Ta-Cheng Hsu ; Yen-Kuang Kuo
Author_Institution :
Inst. of Photonics, Nat. Changhua Univ. of Educ., Changhua, Taiwan
Abstract :
The improvement in efficiency of nitride-based light-emitting diodes by the implementation of a vertically stacked tandem structure is investigated. The electrical and optical characteristics of an LED with a tunnel junction inserted between two active regions are modeled, and the wall-plug efficiency gain of the tandem LED is shown to start at 4.2% at low output powers (27.6 mW), with increasing efficiency gains with increased output power due to the alleviation of efficiency droop. The TLED concept further enables optimization of device structure, allowing removal of electron blocking layer, and optimization of number of quantum wells for improvement in efficiency.
Keywords :
III-V semiconductors; gallium compounds; light emitting diodes; optimisation; semiconductor device models; semiconductor quantum wells; wide band gap semiconductors; GaN; TLED; device structure optimization; efficiency droop; efficiency improvement; electrical characteristics; electron blocking layer removal; light emitting diodes; optical characteristics; quantum wells; tunnel junction; vertically stacked tandem structure; wall-plug efficiency gain; Conductivity; Gallium nitride; Materials; Power generation; Radiative recombination; Superluminescent diodes; Light emitting diodes; semiconductor device modeling; wide band gap semiconductors;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2014.2313953
