Control of electrons and holes by quantum rings and related nanostructures and its device applications

为了扩大纳米电子学研究的前沿，我们探索了量子环（QR）结构与量子点（QDs）、棒和线平行的潜力。人们的注意力主要集中在II型GaSb基纳米结构上，其中空穴被选择性地限制，而电子被驱动到外面。研究了（GaAl）Sb QRs自组织形成的两种方案；在一种方案中，空穴形成环状量子态，而在另一种方案中，电子被限制在带正电的GaSb量子点外的环状轨道中。提出并分析了利用QR态产生多极辐射的可能性。提出并实现了一种新的光电探测器装置，该装置将光产生的空穴捕获在GaSb空穴中，并通过近通道调制电流。此外，我们还展示了一种独特的方案，可以沿周期性约20-40nm的多原子步长排列InGaAs量子点，以及基于附着在单个InAs量子点上的微小电极的新型单电子晶体管。

To expand the forefront of nanoelectronics research, we have explored potentials of quantum ring (QR) structures in parallel with quantum dots (QDs), rods, and wires. Attentions have been focused mainly on type II GaSb based nanostructures, where holes are selectively confined, while electrons are driven outside. Two schemes for the self-organized formation of (GaAl)Sb QRs have been studied; in one scheme, ring-shaped quantum states of holes are formed, whereas electrons are confined in ring-like orbits just outside a positively charged GaSb QD in the other. A possibility to generate multi-pole radiations by making use of QR states has been proposed and analyzed. A new photodetector device has been proposed and realized, in which photo-generated holes are trapped by GaSb holes and modulate the current flow through a near bye channel. In addition, we have demonstrated a unique scheme to align InGaAs QDs along multi-atomic steps of about 20-40nm in periodicity and also novel single-electron transistors based on tiny electrodes attached to an individual InAs QD.