Epitaxial Ag Island - Ge/Si(100) Quantum Dot Nanocomposites for Enhanced Si-Based Light Emission

技术：该项目旨在赋予硅兼容材料增加光学功能。将研究在Ge/Si（100）量子点（QDs）附近排列Ag岛的外延结构，以评估等离子体对发光效率的增强。Ag岛的局部表面等离子体（LSP）模式可以改善锗量子点对光子的吸收和发射。银纳米颗粒附近的强场浓度增加了吸收。珀塞尔效应增加了自发发射速率。最近的理论研究表明，当LSP共振频率接近QD激子的频率时，最佳排列的Ge点和Ag岛的等离子体增强将是最大的。Ag岛的近紫外LSP共振将通过形状共振效应的组合和改变它们的介电环境来调谐，以匹配Ge/Si（100）量子点的近红外激子能量。在理想情况下，理论预测发光增强可以接近两个数量级。一个焦点将是确定覆盖埋藏的Ge点的Si层的非均匀应变平面是否会影响银岛成核的热力学或动力学。第二个重点是在完成硅帽层之前，在Ge点上方发现的纳米级凹坑。非技术：这个项目将积极影响参与研究的学生的教育和未来的职业生涯。他们将在快速发展的等离子体领域的材料和结构的合成以及结构和光学表征方面接受培训。此外，将建立由亚利桑那州立大学Leroy Eyring固态科学中心提供的非常成功的“科学是有趣的”项目的链接。这个项目每年平均影响12000名高中生和中学生。PI将与《科学是乐趣》的员工和实习生密切合作，开发适合年龄的实践活动，展示光与光子结构的相互作用，使用自然产生的蝴蝶翅膀，鸟羽毛和贝壳作为？注意吸引力?。

Technical: This project seeks to endow Si-compatible materials with increased optical functionality. Epitaxial architectures that arrange Ag islands in proximity to Ge/Si(100) quantum dots (QDs) will be investigated to assess plasmonic enhancements to luminescence efficiency. The localized surface plasmon (LSP) mode of the Ag island is predicted to improve both the absorption and emission of photons by the Ge QD. Increased absorption results from the dramatic field concentration near the Ag nanoparticle. The Purcell effect increases the spontaneous emission rate. Recent theoretical work suggests that plasmonic enhancements will be greatest for optimally arranged Ge dots and Ag islands if the LSP resonance frequency is close to that of the QD exciton. The near UV LSP resonance of the Ag islands will be tuned to match the near IR exciton energy of the Ge/Si(100) QDs using a combination of shape resonance effects and by varying their dielectric environment. In the ideal case, theory predicts the luminescence enhancement can approach two orders of magnitude.One focus will be to determine whether the inhomogeneously strained planar surface of the Si layer that caps the buried Ge dots can affect the thermodynamics or kinetics of Ag island nucleation. The second focus will be on the nm-scale pits found immediately above the Ge dots just prior to completion of the Si cap layer. Non-technical: this project will positively affect the education and future career of the student(s) involved in the research. They will be trained in the synthesis as well as the structural and optical characterization of materials and architectures in the rapidly growing field of plasmonics. Additionally, links to the highly successful Science is Fun program offered by the Leroy Eyring Center for Solid State Science at ASU will be established.This program impacts on average 12,000 high and middle school students annually. The PI will work closely with Science is Fun staff and interns to develop hands-on, age-appropriate activities that demonstrate interaction of light with photonic structures using naturally occurring butterfly wings, bird feathers and seashells as ?attention grabbers?.