Influences of Alloy Disorder and Interface Roughness on Optical Spectra of InGaAs/GaAs Strained-Layer Quantum Wells
合金无序和界面不平整对InGaAs/GaAs应变量子阱光谱展宽的影响

We present studies of alloy composition and layer thickness dependences of exciton linewidthsin InGaAs/GaAs strained-layer quantum well grown by MBE, using both photoluminescenceand optical absorption. It is observed that linewidths of exciton spectra increase withindium content and well size.Using the virtual crystal approximation, the experimental dataare analyzed.The results obtained show that the alloy disorder is the dominant mechanismfor line broadening at low temperatures.ln adeition,it is found that the absorption spectrumrelated to light hole transitions has varied from a peak to step-like structure as the temperatureincreases.This behavior can be understood by the space-indirect transition of lightholes.