Excitonic optical transition in a new II-VI semiconductor superlattice

II-VI半导体，如ZnSe，不仅对蓝色半导体激光器的应用有吸引力，而且从物理性质（如大激子结合能）方面也有吸引力。我们已经提出了ZnSe/MgSSe超晶格，并一直在研究这种超晶格中与激子相关的光学跃迁。首先，我们证明了ZnSe/MgS超晶格可以通过金属有机气相外延生长。超晶格的结晶性能主要依赖于GaAs的初始生长，因此研究了表面清洁条件（如金属有机as流动）。研究结果表明，在优化条件下生长的ZnSe/MgS超晶格中，可以很好地分辨出单分子光致发光峰，提高了异质界面的原子突发性。在此基础上，用高分辨率x射线衍射仪对超晶格晶体结构进行了研究。观察到清晰的超晶格卫星峰。从第0峰的位移可以看出MgSe界面层的形成。在异质界面处生长中断改善了这一点。在室温下的反射光谱中可以清晰地观察到激子峰，这表明激子的量子约束增强了。这种超晶格的光致发光也被证明是激子的，直到室温。

II-VI semiconductors such as ZnSe are attractivenot only for the application of blue semiconductor lasers but also from physical properties such as large exciton binding energies. We have proposed ZnSe/MgSSe superiattices and have been working on the exciton related optical transitions in this superlattice.First of all we have demonstrated that the zincblende ZnSe/MgS superlattice can be grown by metalorganic vapor phase epitaxy. The crystalline properties of the the superlattice was critically dependent on the initial growth on GaAs, and therefore the surface cleaning conditions such as metalorganic As flow were examined.With these studies, we could improve the atomic abruptness of the heterointerface and monolayr photoluminescence peaks were well resolved in the ZnSe/MgS superlattice grown with the optimized condition.Based on these growth study, the superlattice crystalline structure was examined with high-resolution X-ray diffraction measurements. Clear superlattice satellite peaks were observed. From the shift of the 0-th peak, we found the formation of the MgSe interface layr. This was improved with growth interruption at the heterointerfaces.Excitonic peaks were clearly observed in the reflection spectra up to room temperature, which indicate the enhancement of quantum confinement on excitons. Photoluminescence from this superlattice was also shown to be excitonic up to room temperature.