宽范围偏置电流下的GaAlAs红外发光二极管1/f噪声特性

在宽范围偏置条件下，测量了GaAlAs红外发光二极管(IRLED)的低频噪声，发现1/f噪声幅值与偏置电流的γ次方成正比，在小电流区，γ≈1，在大电流区γ≈2.基于载流子数涨落和迁移率涨落机制建立了一个GaAlAs IRLED 1/f噪声模型，该模型的分析表明，低电流区GaAlAs IRLED的1/f噪声源于体陷阱对载流子俘获和发射导致的扩散电流涨落，高电流区的1/f噪声源于结空间电荷区附近氧化层陷阱对该处表面势的调制而引起载流子表面复合速率的涨落.该研究结果为1/f噪声表征GaAlAs IRLED的可靠性提供了实验基础与理论依据.

1/f Noise of GaAlAs IREDs Over a Wide Range of Bias Currents

1/f noise in GaAlAs double hetero junction infrared ray LEDs (IRLEDs) is experimental and theoretical studied over a wide range of bias currents.Experimental results demonstrate that the magnitude of 1/f noise is in proportion to the bias current (I_F) in the range below 3 mA,and tends to saturate when the current increases from 3 mA to 5 mA.While,in the current range above 5 mA,the magnitude of 1/f noise increases sharply and is proportional to I2_F.Base on the mechanisms of carrier number fluctuations and carrier velocity fluctuations, a model for 1/f noise in GaAlAs IRLEDs is developed.It is discussed from the model that at small currents,1/f noise in GaAlAs IRLEDs comes from trapping and detrapping process between defects in the bulk region of devices (bulk defects) and carriers,which reveals characteristics of bulk defects.While,at large currents,it is due to fluctuations in the surface recombination velocity induced by the surface potential,which is modulated by oxide traps near the space-charge region, at these conditions,1/f noise reveals defects in the active region of devices (actives defects).1/f noise can be used as a sensitive and non-destructive reliability indicator to probe defects in different regions of GaAlAs IRLEDs.