GaAs/Al_xGa_(1-x)As表面单量子阱原位光调制反射光谱研究

IN-SITU PHOTO\|MODULATED REFLECTANCE STUDY ON GaAs/Al_x Ga_(1-x)As SINGLE SURFACE QUANTUM WELLS

用分子束外延 (MBE)方法生长了两种典型阱宽 (5nm和 10nm)的表面单量子阱 ,表面量子阱中的受限态被表面真空势垒和AlxGa1-xAs势垒束缚 .以原位光调制光谱 (PR)作为测量手段 ,明确观察到表面量子阱中空穴子带到电子子带的光跃迁以及真空势垒对于不同阱宽表面量子阱中的受限电子态的束缚作用 ,并且看到了 10nm表面量子阱激发态的跃迁峰 .采用有效质量近似理论对实验结果作了较好的解释 .

We have studied the optical properties of surface quantum wells with different width of wells (5nm and 10nm) by means of In-situ photo-modulated reflectance(PR) spectroscopy on a molecular beam epitaxy system. The surface quantum well is confined on one side by the vacuum and on the other side by AlxGa1-xAs barrier. In experiments, we have observed clearly the transitions between the confined heavy and light hole states to the confined electron states. The transitions of the excited states in 10nm surface quantum well are observed at first. The effects of the surface on the confined states have been well studied by combination of the PR spectra and the effective mass approximation theory.