Excitonic optical transition in a new II-VI semiconductor superlattice

ZnSe等II-VI族半导体不仅在蓝色半导体激光器的应用中具有吸引力，而且还具有大激子结合能等物理特性。我们提出了ZnSe/MgSSe超晶格，并对这种超晶格中与激子相关的光跃迁进行了研究。首先，我们证明了ZnSe/MgS超晶格可以用金属有机物气相外延生长。超晶格的结晶性质与GaAs上的初始生长密切相关，因此，我们研究了表面清洁条件，如金属有机As流，通过这些研究，我们可以改善异质界面的原子不连续性，并且在优化条件下生长的ZnSe/MgS超晶格中，单层光致发光峰得到了很好的分辨。用高分辨率X射线衍射测量检查超晶格晶体结构。观察到清晰的超晶格卫星峰。从第0峰的位移，我们发现了MgSe界面层的形成。在室温下的反射光谱中可以清晰地观察到激子峰，这表明激子的量子限制增强。从这个超晶格的光致发光也被证明是激子到室温。

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.