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|Title: ||Improvement of Ultra-deep Ultraviolet Light Emitting Diodes with Asymmetric Active Region|
|Authors: ||Huang, Man-Fang;Lu, Tsung-Hung|
|Keywords: ||AlGaN;Light-emitting diodes;Simulation;Polarization effect;Asymmetric active region;Deep UV|
|Issue Date: ||2012-08-07T06:20:41Z
|Publisher: ||International Society for Optical Engineering|
|Abstract: ||We have theoretically investigated the optimized quantum well structure for the ultra-deep ultraviolet (UV)|
AlGaN light emitting diodes (LEDs) with the consideration of band structure deformation caused by polarization effect.
In this paper, we further employ an asymmetric active region to reduce the polarization field in the well-barrier interface
and modify the band structure to enhance the power efficiency of the AlGaN LED. By increasing the thickness of p-side
barrier from 5 nm to 15 nm, the deformation slope of energy band in the well region is reduced due to the reduction of
polarization field, which is caused by the large polarization charges in the interface of p-side barrier and carrier blocking
layer. Accordingly, the hole concentration is increased and the carrier distributions are more uniform caused by the lesstilted
energy band in the well. Therefore, a higher recombination rate and a higher output power can be obtained.
Moreover, the power efficiency of AlGaN LED is barely related to the n-side barrier thickness due to the less
polarization field. However, a thinner n-side barrier is preferred to enhance the current spreading. Therefore, an
asymmetric QW with a thinner n-side barrier and a thicker p-side barrier is a better choice to enhance the power
efficiency for the deep UV AlGaN LED.
|Relation: ||Proc. of SPIE, 6134: 61340O1-8|
|Appears in Collections:||[光電科技研究所] 會議論文|
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