结构缺陷破坏led亮度
逐渐褪色,这是大多数LED故障的原因,主要是由于半导体芯片中的微裂纹。这些缺陷是在复杂的晶圆制造过程中引入的。
称为位错,这些微裂纹增加随着时间的推移越来越快时,LED暴露于高温的地方的数目增加芯片的电荷载体可以重组不产生光(见高新区第“了解导致衰落在高亮度发光二极管”)。
然而,这种所谓的“非辐射复合”的增加并不是导致LED失效的唯一机制。螺纹位错也为泄漏电流创造了路径,剥夺了更有价值的电荷载体的领导地位。随着缺陷的增多,情况变得更糟,导致电源尖峰或静电放电(ESD)事件发生故障的风险增加。
本文介绍了为什么漏电流发生,并建议如何在LED的使用寿命中减缓恶化的进程,这样芯片就可以保证这些固态光源的寿命。
The perils of leakage current
In an operating LED, charge carriers—electrons and holes—migrate to the device’s p-n junction where there is a good chance they will recombine. Recombination (sometimes) releases light in the visible part of the spectrum. (The previous TechZone article cited above describes in detail the physics behind electroluminescence, the phenomenon behind LED light emission.)
The physics of electroluminescence is governed by quantum mechanics, and quantum mechanics allows electrons and holes to do some weird things. One particular quirk is “tunneling” whereby an electron can surmount a barrier (for example, the energy gap across a p-n junction) that, according to classical physics, would require more energy to cross than the electron possesses. It is a bit like weakly rolling a ball up a steep hill, and, instead of seeing it roll back down the hill, observing the ball burrowing through the hill and appearing on the other side.
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