Driving Current Dependence of Emission Spectra and Spectro-color Characteristics of InGaN Based LEDs

测量了InGaN蓝色发光二极管 (LED)在不同正向电流IF 驱动下的发射光谱、色品坐标、光通量、光效等性质的变化。探讨了它们与IF 的依赖关系。结果表明 ,发射光谱和峰值波长λp 随电流IF 从 5mA～ 2 0mA增加 ,发生蓝移 ,当IF 大于 2 5mA直到 5 0mA后 ,λp 又逐渐红移 ,光谱的半高宽 (FWHM)和色坐标x和y值也发生变化 ,光通量呈亚线性增加 ,而光效下降。解析随IF 增加 ,影响蓝光LED性能的因素是多方面的。此外 ,还发现EL光谱中有弱的紫外光辐射。The emission spectra,chromaticity coordinates,luminous flux and luminous efficacy of the InGaN\|based blue LEDs have been measured.The results indicated that as driving current incredses range from 5mA to 20mA,the spectrum morphologies and the peak wavelength λ p have slightly shifted toward short\|wavelength(blue\|shift) and luminous flux has enhanced due to radiation recombination of the D\|A pairs localized energy state in the InGaN well layer.When continuativly increasing forward current,a slowly red\|shift of the emitting peak wavelength λ p and reduction of the luminous efficiency have been observed due to the temperature dependence of band\|gap energy.On the other hand,the weak UV radiation peak about 358nm of the blue LEDs under a forward current of 20 mA has also been observed

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