Recent progress and future prospects of AlGaN-based high-efficiency deep-ultraviolet light-emitting diodes
Recent progress and future prospects of AlGaN-based high-efficiency deep-ultraviolet light-emitting diodes
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DOI：
10.7567/jjap.53.100209
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发表时间：
2014-10-01
影响因子：
1.5
通讯作者：
Kamata, Norihiko
中科院分区：
文献类型：
--
作者：
Hirayama, Hideki;Maeda, Noritoshi;Kamata, Norihiko
本文介绍了AlGaN基深紫外发光二极管（LED）的最新进展。220-350-nm波段深紫外LED已经通过开发用于宽带隙AlN和AlGaN半导体的晶体生长技术而实现。通过在蓝宝石衬底上生长低穿透位错密度（TDD）的AlN缓冲层，AlGaN深紫外发射的内量子效率（IQE）显著提高。通过引入多量子势垒（MQB），LED的电子注入效率（EIE）也显著增加。我们还讨论了光提取效率（LEE），这是实现高效率DUV LED的最重要参数。我们成功地改善LEE通过开发一个透明的p-AlGaN接触层。对于279 nm DUV LED，获得的最大外部量子效率（EQE）为7%。在不久的将来，通过利用透明接触层和光子纳米结构来改善LEE，EQE可以提高高达几十个百分点。(C)2014日本应用物理学会
In this paper, recent advances in AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) are demonstrated. 220-350-nm-band DUV LEDs have been realized by developing crystal growth techniques for wide-bandgap AlN and AlGaN semiconductors. Significant increases in internal quantum efficiency (IQE) have been achieved for AlGaN DUV emissions by developing low-threading-dislocation-density (TDD) AlN buffer layers grown on sapphire substrates. The electron injection efficiency (EIE) of the LEDs was also significantly increased by introducing a multiquantum barrier (MQB). We also discuss light extraction efficiency (LEE), which is the most important parameter for achieving high-efficiency DUV LEDs. We succeeded in improving LEE by developing a transparent p-AlGaN contact layer. The maximum external quantum efficiency (EQE) obtained was 7% for a 279 nm DUV LED. EQE could be increased by up to several tens of percent through the improvement of LEE by utilizing transparent contact layers and photonic nanostructures in the near future. (C) 2014 The Japan Society of Applied Physics