Improving Light Output Power and Thermal Stability for Nitride-based Light Emitting Diodes by Improved Current Spreading

藉由提昇電流散佈能力改善氮化鎵系列發光二極體之光輸出功率與溫度穩定性之研究

在本研究中，我們分析了改變不同電流阻擋層之氮化物系列發光二極體其內部量子效率與注入電流密度之間的關係。結果顯示，較寬的電流阻擋層之發光二極體因為具有較均勻的電流散佈所以其效率衰減的幅度會降低。而較均勻的電流散佈除了提升有效發光面積外，也使電流注入變得更有效率。除此之外，因為改善了電流擁擠的現象，具有較寬之電流阻擋層的發光二極體在操作溫度方面也會因此降低。

In this study, nitride-based light emitting diodes (LEDs) with different current blocking layer (CBL) width are used to elucidate the relationship between injection current density and internal quantum efficiency (IQE). The results indicate that the efficiency droop is improved in the LED with wider CBL region at a higher current density. This is due to superior current spreading. Better current spreading not only increases the effective emitting area but also improves the effective injection current density. In addition, the operating temperature of the LED with the wider CBL region is lower than the others due to the reduction in the current crowding effect.