Temperature-dependent study on AlGaN-based deep ultraviolet light-emitting diode for the origin of high ideality factor
Temperature-dependent study on AlGaN-based deep ultraviolet light-emitting diode for the origin of high ideality factor
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AlGaN基深紫外发光二极管高理想因子起源的温度依赖性研究
DOI：
10.1063/5.0059256
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发表时间：
2021-10-01
期刊：
影响因子：
1.6
通讯作者：
Wang, Zhong Lin
中科院分区：
文献类型：
--
作者：
Liao, Yanjun;Li, Ding;Wang, Zhong Lin
深紫外发光二极管（DUV LED）是用于消毒的有前途的光源，特别是在新型冠状病毒（COVID-19）大流行期间。尽管在深紫外LED的发展中付出了很多努力，但器件温度和理想因子是器件的关键参数，这常常被忽视。在这里，我们开发了一种简单方便的方法来研究280 nm AlGaN基DUV LED的行为，在一次测量中获得电学，光学和热学特性。从实验结果中，我们发现的AlGaN基深紫外LED的光输出功率和墙插效率的强烈影响的器件温度，理想因子（β），和串联电阻（Rs）。当温度从302 K升高到317 K时，在40 mA时，β从9.3降低到8.1。我们将这些结果与模拟结果进行了比较，发现器件内部的高势垒和n型或p型层中的载流子浓度，特别是p型层中的空穴浓度，是LED结构理想因子高值的两个关键因素。随着器件温度的升高，具有较高能量的载流子将克服一些势垒，Mg受体激活将更有效，这有利于载流子输运。然而，这些也导致载流子溢出，削弱了辐射复合率。器件温度在载流子输运和溢出之间的权衡作用是未来开发更高效率和更高亮度的深紫外LED时需要考虑的问题。
Deep ultraviolet light-emitting diodes (DUV LEDs) are promising light sources for disinfection, especially during the pandemic of novel coronavirus (COVID-19). Despite much effort in the development of DUV LEDs, the device temperature and ideality factor are key parameters of devices, which are often neglected. Here, we developed a simple and convenient method to study the behavior of a 280 nm AlGaN-based DUV LED, obtaining the electrical, optical, and thermal properties within one measurement. From the experimental results, we find that the light output power and wall-plug efficiency of the AlGaN-based DUV LED are strongly affected by device temperature, ideality factor (beta), and series resistance (R-s). beta decreases from 9.3 to 8.1 at 40 mA when the temperature increases from 302 to 317 K. We compared these results with simulations and found that the high potential barriers inside the device and the carrier concentration in n-type or p-type layers, especially the hole concentration in p-type layers, are the two key factors for the high value of the ideality factor from the LED structure. As the device temperature increases, carriers with higher energy would overcome some potential barriers and Mg acceptor activation would be more efficient, which are beneficial for carrier transportation. However, these also lead to the carrier overflow and weaken the radiative recombination rate. The trade-off role of device temperature in carriers between transportation and overflow is needed to be considered in the future development of DUV LEDs with higher efficiency and higher brightness.