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Electronic properties and transition processes in semiconductor quantum box structures and artificially localized states (super-donors)

半导体量子盒结构和人工局域态（超级施主）的电子特性和跃迁过程

基本信息

批准号：
04402030
负责人：
SAKAKI Hiroyuki
金额：
$ 10.5万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

As for artificially localized states, namely, the magnetic quantum box (Mag-QB) systems consisteing of quantum wells at magnetic fields, Coulomb quantum box (Imp-QB) systems formed at impurity, levels in quantum wells, and quantum boxes by nanofabrication technique (Fab-QB), we have studied following three subjects.First, we observed longitudinal magnetophonon resonances in superlattices, tunnelling processes through Landau levels in triple barrier tunnel diodes at magnetic fields, and two-dimension (2D) -0D-2D tunnelling through donor levels in double barrier tunnel diodes. In addition, we observed turnstile motion and photon-assisted tunnelling in an electron-beam-fabricated QB.We also fabricated self-assembled InAs quantum boxes and carried out transport measurements.Second, we examined energy relaxation in super-donor levels in order to clarify presence of phonon bottle-neck both theoretically and experimentally. Our theory showed existence of phonon bottle-neck, and Bloch oscillations in 1D coupled quantum box structures due to suppression of phonon scattering. However, the possibility of relatively fast decay within a few meV at resonance relating to both optical and accoustical scatterings were demonstrated. Experimentally, both transport properties of a triple barrier resonant tunnel structure at magnetic fields and optical analysis of a fast relaxation process in electron-hole systems in quantum wells at magnetic fields suggested presence of fast relaxation process.Third, as for photon excitation and ionization of super-donor states, we investigated controllability of donor levels, temperature dependences of conductivity, and infrared response by introducing Si acceptors in (311) A quantum wells.

对于人工定域态，即磁场中量子威尔斯阱构成的磁量子盒（Mag-QB）系统、杂质中量子威尔斯阱能级构成的库仑量子盒（Imp-QB）系统和纳米纤维技术形成的量子盒（Fab-QB）系统，我们主要研究了以下三个方面的问题：首先，我们观察到了超晶格中的纵向磁声子共振;在磁场下通过三势垒隧道二极管中的朗道能级的隧穿过程，以及通过双势垒隧道二极管中的施主能级的二维（2D）-0D-2D隧穿。此外，我们还在电子束制备的量子点中观察到了旋转门运动和光子辅助隧穿现象。我们还制备了自组装InAs量子盒并进行了输运测量。其次，我们研究了超施主能级的能量弛豫，从理论和实验上阐明了声子瓶颈的存在。我们的理论表明，由于声子散射的抑制，一维耦合量子盒结构中存在声子瓶颈和Bloch振荡。然而，在几毫电子伏的共振有关的光学和声学散射的相对较快的衰减的可能性进行了论证。实验上，三势垒共振隧穿结构在磁场下的输运性质和量子威尔斯阱中电子-空穴系统在磁场下的快速弛豫过程的光学分析都表明了快速弛豫过程的存在。第三，对于超施主态的光子激发和电离，我们研究了施主能级的可控性，电导率的温度依赖性，以及在（311）A量子威尔斯阱中引入Si受体的红外响应。