中国物理B ›› 2019, Vol. 28 ›› Issue (1): 17203-017203.doi: 10.1088/1674-1056/28/1/017203

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Current diffusion and efficiency droop in vertical light emitting diodes

R Q Wan(万荣桥), T Li(李滔), Z Q Liu(刘志强), X Y Yi(伊晓燕), J X Wang(王军喜), J H Li(李军辉), W H Zhu(朱文辉), J M Li(李晋闽), L C Wang(汪炼成)   

  1. 1 State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
    2 Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
    3 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101408, China
  • 收稿日期:2018-06-21 修回日期:2018-11-07 出版日期:2019-01-05 发布日期:2019-01-05
  • 通讯作者: L C Wang E-mail:liancheng_wang@csu.edu.cn,wanglc@semi.ac.cn
  • 基金资助:

    Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB0406702), the Professorship Start-up Funding (Grant No. 217056), the Innovation-Driven Project of Central South University, China (Grant No. 2018CX001), the Project of State Key Laboratory of High-Performance Complex Manufacturing, Central South University, China (Grant No. ZZYJKT2018-01), and Guangzhou Science & Technology Project of Guangdong Province, China (Grant Nos. 201704030106 and 2016201604030035).

Current diffusion and efficiency droop in vertical light emitting diodes

R Q Wan(万荣桥)1, T Li(李滔)1, Z Q Liu(刘志强)2,3, X Y Yi(伊晓燕)2,3, J X Wang(王军喜)2,3, J H Li(李军辉)1, W H Zhu(朱文辉)1, J M Li(李晋闽)2, L C Wang(汪炼成)1   

  1. 1 State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
    2 Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
    3 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101408, China
  • Received:2018-06-21 Revised:2018-11-07 Online:2019-01-05 Published:2019-01-05
  • Contact: L C Wang E-mail:liancheng_wang@csu.edu.cn,wanglc@semi.ac.cn
  • Supported by:

    Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB0406702), the Professorship Start-up Funding (Grant No. 217056), the Innovation-Driven Project of Central South University, China (Grant No. 2018CX001), the Project of State Key Laboratory of High-Performance Complex Manufacturing, Central South University, China (Grant No. ZZYJKT2018-01), and Guangzhou Science & Technology Project of Guangdong Province, China (Grant Nos. 201704030106 and 2016201604030035).

摘要:

Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes (LEDs) needs to be further quantitatively clarified. By incorporating current crowding effect (CCE) into the conventional ABC model, we have theoretically and directly correlated the current diffusion and the internal quantum efficiency (IQE), light extraction efficiency (LEE), and external quantum efficiency (EQE) droop of the lateral LEDs. However, questions still exist for the vertical LEDs (V-LEDs). Here firstly the current diffusion length Ls(I) and Ls(Ⅱ) have been clarified. Based on this, the influence of CCE on the EQE, IQE, and LEE of V-LEDs were investigated. Specifically to our V-LEDs with moderate series resistivity, Ls(Ⅲ) was developed by combining Ls(I) and Ls(Ⅱ), and the CCE effect on the performance of V-LEDs was investigated. The wall-plug efficiency (WPE) of V-LEDs ware investigated finally. Our works provide a deep understanding of the current diffusion status and the correlated efficiency droop in V-LEDs, thus would benefit the V-LEDs' chip design and further efficiency improvement.

关键词: efficiency droop, vertical light emitting diodes, current crowding effect, current blocking layer

Abstract:

Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes (LEDs) needs to be further quantitatively clarified. By incorporating current crowding effect (CCE) into the conventional ABC model, we have theoretically and directly correlated the current diffusion and the internal quantum efficiency (IQE), light extraction efficiency (LEE), and external quantum efficiency (EQE) droop of the lateral LEDs. However, questions still exist for the vertical LEDs (V-LEDs). Here firstly the current diffusion length Ls(I) and Ls(Ⅱ) have been clarified. Based on this, the influence of CCE on the EQE, IQE, and LEE of V-LEDs were investigated. Specifically to our V-LEDs with moderate series resistivity, Ls(Ⅲ) was developed by combining Ls(I) and Ls(Ⅱ), and the CCE effect on the performance of V-LEDs was investigated. The wall-plug efficiency (WPE) of V-LEDs ware investigated finally. Our works provide a deep understanding of the current diffusion status and the correlated efficiency droop in V-LEDs, thus would benefit the V-LEDs' chip design and further efficiency improvement.

Key words: efficiency droop, vertical light emitting diodes, current crowding effect, current blocking layer

中图分类号:  (Other topics in electronic transport in condensed matter)

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