异质周期结构稀磁半导体量子输运性质研究

Heterogeneous periodic structure in diluted magnetic semiconductor is a quantum ordered state that spin-polarized electron - hole pairs are effectively isolated and periodically arranged, with spin-dependent resonant tunneling that barrier and potential well, and the electron spin and transport can be manipulated through applied electric field, magnetic field, light irradiation. Therefore, diluted magnetic semiconductor heterogeneous periodic structure is an ideal carrier for studying quantum ordered state and spin-dependent resonant tunneling. This project prepares room temperature ferromagnetism p-type and n-type In2S3 dilute magnetic semiconductor nanoparticles by using nano magnetic assembly method. And assembles them into a quasi-two-dimensional p-n heterojunction structure array arranged in a multi-component. The microscopic mechanism is studied systematically combined with the crystal growth theory, the interface surface dynamics and statistical thermodynamic theory. A controlled and orderly preparation technique of In2S3-based p-n diluted magnetic nano heterojunction structure array is expected to obtains. We look forward to summarize regulated quantum ordered state,explore the physical origin of spin-dependent resonant tunneling coupling and synergy effect in dilute magnetic nano heterostructure system, develops relevant theories and provide important experimental and theoretical basis for the design and application of new quantum state materials.

稀磁半导体异质周期结构是一种量子有序态，自旋极化的电子-空穴对有效分离并周期排列，具有自旋相关的共振隧穿，通过外加电场, 磁场，光辐照可以操纵势垒和势阱，以及电子自旋和输运，是研究量子有序态和自旋相关的共振隧穿理想载体。本项目采用纳米磁组装方法，制备室温铁磁性p型和n型In2S3稀磁半导体纳米颗粒，并将其组装成多组分排列的准二维异质p-n结构阵列；结合晶体生长理论，表面界面动力学和统计热力学理论，系统研究微观机制；获得In2S3基p-n稀磁纳米异质结构阵列的可控和有序化制备技术。总结出可调控的量子有序态，探讨出稀磁纳米异质结构体系自旋相关的共振隧穿耦合与协同效应物理根源，发展相关理论，为制备新型量子态材料设计和应用提供重要的实验和理论依据。

以In2S3半导体量子点为基础，通过掺杂不同浓度的稀土离子Eu3+、Ce3+、Tb3+、Ho3+、Cd3+、Dy3+，制备出一系列具有磁学性质的荧光量子点材料。探讨了不同掺杂对这些量子点材料光学和磁学性质的影响规律，并结合VASP第一性原理计算对各个体系的电子能带结构和态密度进行了系统分析，探索了其内在物理机制。纳米异质结构阵列材料具有多重异质结势垒的能级结构，其导电性主要受异质结势垒高度控制。载流子在这种异质结构材料中是以量子共振隧穿形式输运的。异质结势垒的高度对载流子浓度变化非常敏感，共振隧穿调制的实现只需要较低水平的载流子浓度变化。在室温条件下，共振隧穿调制过程也具有反应速度快和容易恢复的特点，气体探测可以在多重异质结势垒的异质结构材料中实现室温探测。项目总结了 In2S3 基稀土掺杂量子点的磁性运转机制和带隙变化规律，为太阳能转换器，投影电视屏幕，生物医学探针和光催化等领域的应用以及自旋光电子器件的发展奠定了实验和理论基础。