Degradation of (InAlGa)N-based UV-B light emitting diodes stressed by current and temperature

摘要: The degradation of the electrical and optical properties (InAlGa)N-based multiple quantum well light emitting diodes (LEDs) near 308 nm under different stress conditions has been studied. LEDs with emission areas were operated at room temperature constant current densities 75 A/cm2, 150 A/cm2, 225 A/cm2. In addition, heat sink was varied between 15 °C 80 °C. Two main modes for reduction power found, which dominate times operation: (1) Within first 100 h, a fast drop is observed scaling exponentially having an activation energy about 0.13 eV. in accompanied by changes current-voltage (I-V) characteristic. (2) For operation beyond decreases slowly can be reasonably described square root time dependence. Here, rate depends on density, rather than current. A...