GaAs/AlGaAs多量子阱结构的热电子效应

HOT ELECTRON EFFECT IN GaAs/AlGaAs MULTIPLE QUANTUM WELLS

采用低温荧光激发光谱（ＰＬＥ）研究了ＧａＡｓ／ＡｌＧａＡｓ多量子阱结构中热电子的弛豫过程，在ＰＬＥ谱中首次观察到ＧａＡｓ／ＡｌＧａＡｓ多量子阱中ＬＯ声子的发射．用四能带Ｋａｎｅ模型计算了由轻、重空穴杂化效应引起的价带结构的畸变及其对声子发射谱的影响．实验和理论计算结果均表明，光激发热电子可以通过发射ＬＯ声子直接弛豫到激子态上。

Hot electron relaxations in GaAs/AlGaAs multiple quantum wells were studied using photoluminescence excitation (PLE) spectroscopy. LO phonon emissions in the quantum wells were observed. A four band Kane model was built to calculate the deformation of sub valence bands due to the mixing effect of heavy and light hole bands. The deformation affects the measured PLE responses. The measured and calculated results show that photo excited electrons can cascade down to the exciton energy state directly by LO phonon emissions.