GaN基蓝光发光二极管峰值波长偏移的研究

Research of Peak Wavelength Shifts of GaN-based Blue Light-emitting Diodes

通过对蓝光和红光发光二极管在直流和脉冲电流两种情况下进行变电流测试,对其峰值波长的偏移情况进行了深入的对比分析和研究,指出主要是热效应和极化效应两个因素造成蓝光LED的峰值波长发生偏移,并计算出热效应单独引起峰值波长偏移的温度系数为0.080 7nm/K,In0.2Ga0.8N/GaN发光二极管量子阱中的极化强度为3.765 0 MV/cm;分析还认为电流注入下多量子阱中载流子分布不均匀也是影响器件峰值波长的一个因素,并计算得到去除极化影响后量子阱中的场强,验证了在电流注入下多量子阱中载流子分布不均匀的结论。

Different shifts of peak wavelengths of blue and red LEDs were studied by measuring the two kinds of LEDs under DC and pulse currents, and it demonstrates that it is the heat and polarization effects that influence the shifts of peak wavelengths. The peak wavelengths＇ shift degree of 0. 080 7 nm/K caused by heat effect alone is calculated, and the electric field intensity caused by polarization is 3. 765 0 MV/cm in the quantum wells of In0.2 Ga0.8 N/GaN LEDs. The asymmetry distribution of carriers in the MQWs is another factors. By calculating the electric field intensity that excluded polarization＇s influence, the conclusion that the carriers are not uniformly distributed in the MQWs under different amounts of current is proved.