Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
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Improvement of Electrical/optical Characteristics Using Mg-doped GaN Spacers and Quantum Barriers for Nonpolar GaN light-emitting Diodes

마그네슘이 도핑된 GaN 공간층과 양자장벽층을 이용한 무분극 GaN 발광다이오드의 전기적/광학적 특성 향상

  • Kim, Dong-Ho (School of Electronics and Electrical Engineering, Korea University) ;
  • Son, Sung-Hun (School of Electronics and Electrical Engineering, Korea University) ;
  • Kim, Tae-Geun (School of Electronics and Electrical Engineering, Korea University)
  • 김동호 (고려대학교 전자전기공학과) ;
  • 손성훈 (고려대학교 전자전기공학과) ;
  • 김태근 (고려대학교 전자전기공학과)
  • Received : 2011.01.18
  • Accepted : 2011.07.06
  • Published : 2011.07.25
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Abstract

We report on the simulation results of electrical/optical characteristics for nonpolar GaN LED having Mg-doped GaN spacer and quantum barrier, in comparison with those of the typical nonpolar GaN LED. In order to reduce the band-gap energy distortion and conduction-band discontinuity in InGaN/GaN multiple quantum wells(MQWs) of nonpolar GaN LED, and thereby to increase their current-voltage, light output power and emission peak intensity, we applied 6 nm-thick p-type($1{\times}10^{18}\;cm^{-3}$) GaN spacer and GaN QB schemes to the typical nonpolar GaN LED epitaxial structure. As a result, we found that the radiative recombination rate was increased by 23% in MQWs at 20 mA current injection. Also, the forward voltage($V_f$) and the light output power($P_{out}$) were improved by 3.7% and 7%, respectively, for the proposed nonpolar LED epitaxial structure, compared with those of the typical nonpolar GaN LED.

본 논문에서는 고효율 고출력 무분극 GaN LED의 구현을 위하여 Mg이 도핑된 GaN spacer층 및 GaN quantum barrier(QB)층을 삽입한 구조를 제안하였다. 제안한 구조에 대한 물리적 해석을 위하여 일반적인 무분극 LED 에피구조와 본 연구에서 제안한 p-GaN spacer층 및 p-GaN QB층이 삽입된 무분극 LED 에피구조에 대해 상용화된 $SimuLED^{TM}$ 시뮬레이터를 이용하여 전기적/광학적 특성을 비교 분석하였다. 실험 결과, 본 연구에서 제안한 무분극 LED는 20 mA의 전류주입 하에서 동작전압($V_f$)이 일반적인 무분극 LED에 비해 약 3.7% 감소된 3.67 V의 전기적 특성을 갖는 것을 확인하였고, 광출력은 약 7% 향상된 2.13 mW의 광학적 특성을 갖는 구조임을 확인하였다. 또한, 내부양자효율(Internal quantum efficiency, IQE)과 광방출세기(emission peak intensity) 역시 각각 9.1% 및 170% 향상된 우수한 특성을 갖는 에피구조임을 확인하였다.

Keywords

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