Intersubband Dynamics in Semiconductor Quantum Wells

这个理论资助的重点是与半导体量子阱中子带间跃迁相关的非线性响应。从GaAs/AlAs和InAs/GaAs系统生长的量子阱中典型的子带分裂位于光谱的远红外到中红外区域-从1到100meV。在宽带隙III-V材料中，如InGaN/GaN和GaN/AlGaN量子阱，可以实现远红外到近红外的子带间分裂。以下项目将被解决：载波拉比跳变：这些是在宽GaAs/AlGaAs量子阱中由强太赫兹脉冲相干地上下驱动两个子带之间的种群振荡。非线性远红外响应：由于子带间跃迁附近的强场驱动的宽n型GaAs/AlGaAs量子阱可能表现出本质上的非线性响应，这是由于子带间等离子激元屏蔽了驱动场。GaN/AlGaN和InGaN/GaN量子阱的子带间载流子动力学：宽禁带氮量子阱可能具有比低禁带半导体中的介电击穿场大~1MV/cm的内置电场。当太赫兹源驱动子带间跃迁时，极化场的动态屏蔽将导致强烈的非线性响应。每个课题都将与密歇根大学、UCSB大学和佐治亚理工学院的实验小组密切合作进行研究。这项理论资助的重点是半导体量子阱中与子带间跃迁相关的非线性响应。这些转变可以导致许多具有基础和应用兴趣的新现象。这项研究将与领先的实验小组密切合作进行

This theoretical grant focuses on the nonlinear response associated with intersubband transitions in semiconductor quantum wells. Typical subband splittings in quantum wells grown from the GaAs/AlAs and InAs/GaAs systems are in the far- to the mid-infrared region of the spectrum - from 1 to 100meV. In wide-bandgap III-V materials, such as InGaN/GaN and GaN/AlGaN quantum wells, intersubband splittings from the far- to the near-infrared are possible.The follwing project swill be addressed:Carrier-wave Rabi flopping: These are population oscillations between two subbands driven coherently up and down by a strong THz pulse in wide GaAs/AlGaAs quantum wells.Nonlinear far-infrared response: A wide n-type GaAs/AlGaAs quantum well driven by a strong field near an intersubband transition may exhibit an essentially nonlinear response owing to intersubband plasmons, which screen out the driving field.Intersubband carrier dynamics in GaN/AlGaN and InGaN/GaN quantum wells: Wide-bandgap nitride quantum wells may possess built-in electric fields as large as ~1MV/cm - in excess of dielectric breakdown fields in lower-bandgap semiconductors. The dynamic screening of this polarization field as an intersubband tranition is driven by a THz source will lead to a strong nonlinear response.Each topic will be studied in close cooperation with experimental groups at Michigan, UCSB and Georgia Tech. %%%This theoretical grant focuses on the nonlinear response associated with intersubband transitions in semiconductor quantum wells. These transitions can lead to many novel phenomena of both fundamental and applied interest. The research will be done in close coordination with leading experimental groups.***