Electric field control of opical transitions in semiconductor superlattice spaces

为了追求半导体量子结构中光学跃迁的电场可控性，我们对三种不同类型的GaAs/AlAs超晶格进行了研究，得到了以下结果。电场对非对称双势垒超晶格中光学跃迁的影响对于单位周期内由非对称双势阱对组成的新型双周期超晶格，观察到并阐明了光学跃迁的反交叉和激子效应，这些效应源于Stark梯形态间的共振耦合，它们分别属于宽势垒和窄势垒。电场对完全不对称双周期超晶格中光学跃迁的影响对于具有势垒和势垒双周期性的新型完全非对称超晶格，通过基于传输矩阵方法的限制本征能和振子强度的理论计算，解释了观察到的跃迁能扇图和由于通过较薄势垒的更强耦合而增强的抗交叉效应。电场对超晶格梯子与单量子井态相互作用引起的光学跃迁的控制在中间含有孤立单量子井的单周期超晶格的光吸收谱中，观察到了外加电场控制的电子和空穴共振，并在有效质量近似下用转移矩阵计算进行了分析。

In order to pursue the electric-field controlability of optical transitions in semiconductor quantum structures, three different-types of GaAs/AIAs superlattices have been investigated and the following results are obtained.1. Electric field effects on optical transitions in an asymmetric double-well superlatticeFor a new-type biperiodic superlattice consisting of asymmetric double-well pairs in a unit period, anticrossings as well as excitonic effects of the optical transitions have been observed and clarified, originating from the resonant coupling between the Stark-ladder states belonging to the wider and narrower wells.2. Electric field effects on optical transitions in a perfectly asymmetric double period superlatticeFor a new-type of perfectly asymmetric superlattice having the well and barrier biperiodicity, the observed transition energy fan diagram and enhanced anticrossings due to stronger couplings through the thinner barriers have been elucidated in the light of theoretical calculations of the confined eigenenergies and the oscillator strengths based on the transfer matrix method.3. Electric field control of optical transitions due to interactions between superlattice ladder and single quantum well statesElectron as well as hole resonances controlled by the applied electric field have been observed in the optical absorption spectra of a monoperiodic superlattice which contains an isolated single quantum well in the middle, and analyzed with the help of transfer matrix calculations within the effective mass approximation.