Research on a single electron transistor with self-assembled quantum dots and its prototype fabrication

我们提出了一种嵌入InAs量子点的异质结构晶体管，它可以操纵量子点中的电子态（包括自旋态）。当沟道电子的自旋可以通过自旋注入方法选择时，沟道附近埋有量子点的异质结构FET具有量子比特（qubit）势。这一设想的实现依赖于Rashba效应控制和自旋注入的成功。本文对这些重要的量子阱的可行性进行了研究和总结。通过对Shubnikov-de哈斯振荡的分析，在InAs衬底上生长的InAs量子阱结构中发现了大的自旋轨道耦合。得到的自旋-轨道相互作用系数为[约等于] 30 × 10 ^<-12>eVm。发现这个数目比GaAs或InGaAs在InP上的数目大得多，并且几乎可以与以前的实验相比较，在以前的实验中，测量的InAs异质结构与可能的界面态或可能的残余应变或几个子能级的相互作用有关。用分子束外延技术在23℃低温下在InAs衬底上生长Fe晶体，可以获得较好的自旋注入特性。测量了自旋极化电子从铁磁体注入InAs的场致发光，证实了自旋极化电子注入的极化度约为20%。

We have proposed a heterostructure transistor embedded with InAs quantum dots which could manipulate electron states (including spin states) in the dot. The heterostructure FET with quantum dots buried in adjacent to the channel, was shown to have apotential of quantum bit ("qubit") when the spin of channel electrons are selectable by spin injection method. Realization of this idea depends on the success of Rashba effect control and spin injection. The feasibility of these important toipcs has been investiagted and summarized below.Large spin-orbit coupling in InAs quantum well structure which was grown on InAs substrate by analyzing Shubnikov-de Haas oscillation. The obtained spin-orbit interaction coefficient was 【approximately equal】 30x10^<-12>eVm. The number was found to be much greater than that of GaAs or InGaAs on InP and almost comparable to the previous experimets where measured InAs heterostructures were associated with possible effects from interface states or possible residual strain or possible interplay of several sublevelsl.The "spin-injection" from ferromagnetic film into semiconductors has been investigated. The crystal Fe growth on InAs by molecular beam epitaxy at low temperature of 23℃ was found to yield better spin injection characteristics. The electroluminescence of spin polarized electrons injected from ferromagnets into InAs therough Fe/InAs junction was measured, and verified spin injection with polarization of 【approximately equal】20%.