注入电流对绿光高压LED光电特性的影响

Effects of Injection Current on Optical and Electrical Properties of GaN-based Green High Voltage LED

设计并制备了12 V的GaN基绿光高压发光二极管(LED),并对其进行了变电流测试.研究了绿光高压LED的正向电压、峰值波长、光功率以及光效等重要参数随注入电流的变化关系,电流变化范围为3～50mA,测试温度为25℃.实验结果表明:电流对绿光高压LED的光电特性有很大影响.在驱动电流为20 mA时,对应电压为14 V.随着注入电流的增大,峰值波长蓝移了2 nm.随着电流的增大,光功率近似于线性增加.在注入电流从3mA增大到20 mA的过程中,光效降低了约61％;在注入电流从20 mA增大到50 mA的过程中,光效降低了约39％.这说明高压LED在大电流驱动时,光效降低的幅度比较缓慢.上述结果对GaN基绿光高压LED的改进优化具有一定的参考价值.

GaN-based green high-voltage (HV) light emitting diodes (LEDs) of 12 V were designed and fabricated. The optical and electrical parameters such as forward voltage, peak of wavelength, optical power, and luminous efficiency were investigated when the injection current varied from 3 mA to 50 mA at 25°C. The results show that the injection current has a great effect on the optical and electrical properties of the GaN-based high-voltage LED. When the current is 20 mA, the corresponding voltage is 14 V. With the increasing of the injection current, the blue-shift of LED peak wavelength reaches 2 nm. In addition, the optical power increases approximately linearly with the current increasing. The luminous efficiency decreases 61% when the injection current increases from 3 mA to 20 mA, and decreases 39% when the injection current increases from 20 mA to 50 mA. It indicates that the luminous efficiency decreases more slowly when the high-voltage LED is driven by large current. These results will have a certain reference value for the improvement and optimization of GaN-based high-voltage LEDs.