Coherence and recombination dynamics of excitons in nanostructures: towards excitonics

纳米结构中激子的相干和复合动力学：走向激子学

• 批准号: 36947-2013
• 负责人: Leonelli, Richard
• 金额: $ 1.53万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633559
• 关键词: Coherence; recombination; dynamics; excitons; nanostructures

When a semiconductor absorbs a photon, an electron is excited to the conduction band, leaving a hole in the valence band. The Coulomb interaction between electrons and holes results in a bound state, the exciton, which controls to a large extent the optical properties of semiconductors. When the semiconductors are structured on a nanometric scale, the exciton optical response is dramatically altered by quantum confinement, localization and delocalization processes, exchange interaction and other many-body effects.My research program is about probing exciton dynamics in the complex energy landscape associated with nanostructures in order to understand how energy is absorbed and redistributed within a collective excitation picture. This issue, which is arguably amongst one of the most exciting in contemporary condensed-matter physics, involves many-body physics within and beyond the perturbative regime. It is also integral to excitonics, which deals with applications, ranging from efficient light emitters to quantum logical devices, where the specific properties of excitons are exploited. The main thrust of my activities is directed towards the three following projects:- Exciton localization and recombination in InGaN/GaN nanowires.- Spontaneous quantum coherence in all-organic microcavities.- Extreme 2D excitons in single-layer chalcogenides.These projects involve materials or systems of high potential technological impact, but where the fundamental processes that control exciton creation, relaxation and recombination are imperfectly, if at all, understood. They thus constitute excellent test beds for strongly correlated electron theories.

当半导体吸收一个光子时，一个电子被激发到导带，在价带上留下一个空穴。电子和空穴之间的库仑相互作用导致束缚态激子，激子在很大程度上控制着半导体的光学性质。当半导体结构在纳米尺度上时，激子的光学响应会受到量子限制、局域和离域过程、交换相互作用和其他多体效应的显著改变。我的研究计划是探索与纳米结构相关的复杂能量格局中的激子动力学，以了解能量是如何在集体激发图中被吸收和重新分配的。这个问题可以说是当代凝聚态物理学中最令人兴奋的问题之一，它涉及微扰区域内外的多体物理。它也是激子电子技术不可或缺的一部分，激子电子技术涉及从高效光发射器到量子逻辑设备的各种应用，在这些应用中，激子的特定属性得到了利用。我的活动主要针对以下三个项目：-InGaN/GaN纳米线中的激子局部化和复合。-全有机微腔中的自发量子相干性。-单层硫化物中的极端2D激子。这些项目涉及具有高潜在技术影响的材料或系统，但控制激子产生、弛豫和复合的基本过程即使有，也是不完全了解的。因此，它们构成了强关联电子理论的极佳试验台。