压电调制反射光谱研究GaAs/Al_(0.29)Ga_(0.71)As单量子阱

Piezomodulated-reflectivity study of GaAs/Al_(0.29)Ga_(0.71)As single quantum well

报道了压电调制反射测量系统的建立,应用该系统获得了势阱宽度分别为5nm和25nm的两个GaAs Al0.29Ga0.71As单量子阱的压电调制反射谱.从图谱中可以看出,在室温下能够较容易地分辨出和轻、重空穴相关联的子带跃迁.在阱宽25nm的样品中还观察到了自旋_轨道跃迁.利用有效质量理论近似计算,对量子阱样品的图谱结构进行了指认,发现实验值和计算值能够较好地符合.

We report here that we have built a set of piezomodulated-reflectivity measurement system, and obtained piezomodulated-reflectivity spectra of two GaAs/Al-0.29 Ga-0.71 As single quantum well samples in which the well widths are 5 and 25nm respectively. From these spectra, the transitions between electron and heavy and light hole subbands can be easily identified. Furthermore, we have observed the optical transition related to spin-orbit split-off of GaAs buffer. Effective mass theory is applied to calculate the transition energy between electron and hole subbands. Then the spectral structures are assigned based on the calculated results. It is found that these calculated results agree with experimental ones very well.