Intersubband Dynamics in Semiconductor Quantum Wells

这理论补助金集中在与半导体量子威尔斯的子带间跃迁相关的非线性响应。 在GaAs/AlAs和InAs/GaAs系统中生长的量子威尔斯中，典型的子带分裂在光谱的远红外到中红外区域-从1到100 meV。 在宽禁带的III-V族材料中，如InGaN/GaN和GaN/AlGaN量子威尔斯阱，从远红外到近红外的子带间分裂是可能的。下面将讨论：载波拉比跳跃：这是宽GaAs/AlGaAs量子威尔斯阱中两个子带之间的布居振荡，由强太赫兹脉冲相干地上下驱动。非线性远红外响应：宽n型GaAs/AlGaAs量子阱在子带间跃迁附近受强场驱动时，由于子带间等离子体激元屏蔽了驱动场，可能会表现出本质上的非线性响应。GaN/AlGaN和InGaN/GaN量子威尔斯中的子带间载流子动力学：宽带隙氮化物量子威尔斯阱可具有高达约1 MV/cm的内建电场-超过较低带隙半导体中的介电击穿场。 这种极化场作为子带间跃迁的动态屏蔽是由太赫兹源驱动的，将会导致强烈的非线性响应。每个课题都将与密歇根大学、加州大学旧金山分校和格鲁吉亚理工学院的实验组密切合作进行研究。 本理论研究主要集中在半导体量子威尔斯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新的现象的基本和应用的兴趣。 这项研究将与主要实验小组密切协调进行。

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.***