Band-engineering using III-V based ferromagnetic semiconductors and its application to magneto-optical devices

我们已经证明，在分子束外延（MBE）生长的基于半导体的多层结构中，磁光特性可以可控地增强，该多层结构由磁性层和GaAs/AlAs分布式布拉格反射器（DBR）组成，DBR是一种基于半导体的一维磁光子晶体。这里，磁性层是含有MnAs纳米级团簇的GaAs(GaAs:MnAs)，它可以通过在500-750℃下对(GaMn)As合金进行退火来形成。介绍了 GaAs:MnAs 的结构和磁光特性，并推导了其介电函数。结果表明，通过 MBE 成功生长了 DBR/GaAs:MnAs/DBR 结构，并且由于光在布拉格波长的局域化，其磁光效应得到增强。还阐明了磁光特性和器件电势与理论计算的比较。此外，利用GaAs:MnAs纳米团簇系统，提出并分析了基于半导体的波导型光隔离器。我们的理论计算表明，TE 模式和 TM 模式操作都可以实现。

We have shown that magneto-optical properties can be controllably enhanced in molecular beam epitaxy (MBE) grown semiconductor-based multilayer structures consisting of a magnetic layer and GaAs/AlAs distributed Bragg reflectors (DBR), that is a one-dimensional semiconductor-based magneto-photonic crystal. Here, the magnetic layer is GaAs containing MnAs nanoscale clusters (GaAs:MnAs), which can be formed by annealing (GaMn)As alloys at 500 - 750℃. Structural and magneto-optical properties of GaAs:MnAs are presented and its dielectric functions are derived. It is shown that DBR/GaAs:MnAs/DBR structures were successfully grown by MBE and their magneto-optical effect is enhanced due to the localization of light at the Bragg wavelength. Comparison with theoretical calculations of the magneto-optical properties and device potentials are also clarified.Furthermore, using the GaAs:MnAs nanocluster system, semiconductor-based waveguide-type optical isolators are proposed and analyzed. Our theoretical calculations have shown that both TE-mode and TM-mode operations can be realized.