ZnSe-ZnTe应变层超晶格的纵光学声子模

LO phonon modes in ZnSe-ZnTe strained-layer superlattice

本文首次利用室温非共振喇曼后向散射测得具有7.3％晶格失配的ZnSe-ZnTe应变层超晶格限制在ZnSe层中的纵光学声子模。计算了限制效应引起的声子模频率的红移,以及弹性应变引起的声子模的移动,它比前者大得多。ZnSe层所受拉伸应变引起声子频率红移,ZnTe层所受压缩应变引起声子频率蓝移。同时在喇曼光谱中观察到由于这种效应导致出现的纵光学声子折叠模。

Using off-resonance Raman scattering at room temperature, we have observed, for the firsttime, the confined longitudinal optical (LO) phonon modes in ZnSe layer of the ZnSe-ZnTe strined layer superlattice(SLS) which have the lattice mismatch as large as 7.3%. The red shifts of LO phonon frequencies induced by confinement and the shifts induced by the elastic strains have been calculated. The latter are much larger than that induced by former. The blue shifts induced by tensile strain in ZnSe layer and thet red shifts induced by comperssive strain in ZnTe layer made some confined LO modes in two individual layers overlap. Therefore, the folded LO mode had been observed in ZnSe-ZnTe SLS.