Efficiency degradation behaviors of current/thermal co-stressed GaN-based blue light emitting diodes with vertical-structure
Efficiency degradation behaviors of current/thermal co-stressed GaN-based blue light emitting diodes with vertical-structure
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DOI：
10.1063/1.4712030
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发表时间：
2012-05-01
影响因子：
3.2
通讯作者：
Wang, Gang
中科院分区：
文献类型：
--
作者：
Liu, Lilin;Ling, Minjie;Wang, Gang
通过这项工作，我们展示了基于 GaN 的 LED 芯片在电流/热共应力下的三阶段退化行为。这三个阶段依次为初始改善阶段、平台阶段和快速退化阶段，表明电流/热共应力同时激活积极作用和消极作用，并且主要的退化机制随着老化时间的推移而演变。讨论了降解机制。电流应力具有双重特征：通过产生缺陷来损坏有源层，同时通过激活镁掺杂剂来提高p型导电性。高温应力会增强电流应力的影响。镁掺杂剂的激活将饱和，而缺陷的产生则以渐进的方式进行。其他机制，例如欧姆接触的恶化，也会起作用。这些机制相互竞争/合作，并随着老化时间的推移而演变，导致观察到的三阶段降解行为。通过具有恒定加速因子的模型来预测 LED 的寿命存在风险。 (C) 2012 年美国物理研究所。 [http://dx.doi.org/10.1063/1.4712030]
With this work, we demonstrate a three-stage degradation behavior of GaN based LED chips under current/thermal co-stressing. The three stages in sequence are the initial improvement stage, the platform stage, and the rapid degradation stage, indicating that current/thermal co-stressing activates positive effects and negative ones simultaneously, and the dominant degradation mechanisms evolve with aging time. Degradation mechanisms are discussed. Electric current stress has dual characters: damaging the active layers by generating defects and at the same time improving the p-type conductivity by activating the Mg-dopant. High temperature stresses will promote the effects from electric current stresses. The activation of the Mg-dopant will saturate, whereas the generation of defects is carried on in a progressive way. Other mechanisms, such as deterioration of ohmic contacts, also operate. These mechanisms compete/cooperate with each other and evolve with aging time, resulting in the observed three-stage degradation behavior. There exist risks to predict the lifetime of LEDs by a model with a constant accelerated factor. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712030]