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Proceedings Paper

Effect of spontaneous and piezoelectric polarization on the optical characteristics of blue light-emitting diodes
Author(s): Yen-Kuang Kuo; Sheng-Horng Yen; Miao-Chan Tsai; Bo-Ting Liou
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Paper Abstract

The effect of spontaneous and piezoelectric polarizations on optical characteristics of blue InGaN light-emitting diodes (LEDs) is investigated in this work with the APSYS simulation program. Specifically, the band diagram, carrier distribution, radiative recombination current, and light-current performance curves are discussed for various polarization situations. According to the simulation results, the amount of polarization charges is dominated by piezoelectric polarization. Therefore, the band diagram and overlap between electrons and holes in quantum wells are improved effectively and the light-current performance is raised apparently as the piezoelectric polarization is removed and only the spontaneous polarization is taken into account. The possible reason is that the influence of piezoelectric polarization due to lattice constant mismatch on optical properties is severe than the spontaneous polarization due to asymmetry of the wurtzite structure along the c-axis. Moreover, the simulation results suggest that the blue InGaN LED structures with spontaneous polarization may provide higher output power but are more sensitive to temperature, in a range from 300 K to 350 K, when compared to the LED structures with piezoelectric polarization.

Paper Details

Date Published: 14 September 2007
PDF: 8 pages
Proc. SPIE 6669, Seventh International Conference on Solid State Lighting, 66691I (14 September 2007); doi: 10.1117/12.733860
Show Author Affiliations
Yen-Kuang Kuo, National Changhua Univ. of Education (Taiwan)
Sheng-Horng Yen, National Changhua Univ. of Education (Taiwan)
Miao-Chan Tsai, National Changhua Univ. of Education (Taiwan)
Bo-Ting Liou, Hsiuping Institute of Technology (Taiwan)

Published in SPIE Proceedings Vol. 6669:
Seventh International Conference on Solid State Lighting
Ian T. Ferguson; Nadarajah Narendran; Tsunemasa Taguchi; Ian E. Ashdown, Editor(s)

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