Investigating the effects of thermal-opto-mechanical interactions on optical responses of multilayer semiconductor nanocrystals

本计画将探讨多层半导体奈米晶体在不同热环境及机械应力下之光学特性。半导体纳米晶体是纳米尺度的晶体颗粒，其物理和光学性质可以通过控制其尺寸和几何形状来调节。本计画将研究在微反应器系统中，以硒化镉、硫化镉及硫化锌为原料，合成多层半导体奈米晶体的特性。对这些多层半导体纳米晶体的热-光-机械性质的全面理解可以导致基于纳米晶体的器件和系统的发展，以及更好的设计方法，用于它们在光机械器件和系统、纳米光子学和生物传感器（例如白色发光二极管）中的应用。 这项研究的结果将有助于加强美国在纳米电子学、太阳能和纳米光子学领域的地位和影响力。这项研究的跨学科性质将有助于美国劳动力通过培养研究生和本科生在材料加工和光子学方面更具竞争力。这些学生将掌握半导体纳米晶体的合成和表征技能，并将发展解决技术问题的技能。研究人员将积极招募女性和代表性不足的少数民族，以促进他们在纳米光子学和生物光子学领域的包容性。半导体纳米晶体作为纳米光子学和生物光子学的潜在构建块，在各种应用中引起了极大的兴趣。全面了解多层半导体纳米晶体的几何尺寸和热-光-机械相互作用对光学特性的影响，可以帮助开发性能更好和更可靠的纳米器件和系统。本研究计划将透过紧密耦合的实验与模拟方法，探讨多层半导体奈米晶体在热机械负载下的光学特性，包括张力、压缩与循环加热-冷却，以及多层半导体奈米晶体的几何尺寸对前驱物浓度、温度与停留时间的依赖性。本论文将发展一种微流控系统中的微反应器来合成多层半导体纳米晶体，并研究在流动环境中控制多层半导体纳米晶体生长的速率机制。研究小组将建立多层半导体纳米晶体的光学性质、应力和温度以及几何尺寸之间的相关性。该团队将开发数值模型，可以定量分析热机械负载下纳米晶体的光学响应。这些关系提供了对半导体纳米晶体中的热-光-机械耦合的基本理解，并且可以为更好地设计具有高性能和可靠性的基于纳米晶体的器件和系统提供指导。学生将接受微流控反应器设计和半导体纳米晶体热光机械行为局部表征技术开发方面的培训。该奖项旨在为高中生和大学生提供开发用于化学反应的微流控系统的设计项目，学生可以从中学习设计有用产品的技术和非技术要求。该奖项反映了NSF的法定使命，通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will investigate the optical characteristics of multilayer semiconductor nanocrystals under different thermal environments and mechanical stresses. Semiconductor nanocrystals are nanoscale crystalline particles with physical and optical properties that are tunable through controlling their size and geometric shape. This project will study the characteristics of multilayer semiconductor nanocrystals made from cadmium selenide, cadmium sulphide and zinc sulphide, which are synthesized in a microreactor system. A comprehensive understanding of the thermal-opto-mechanical properties in these multilayer semiconductor nanocrystals can lead to the development of nanocrystal-based devices and systems, as well as better design approaches for their applications in optomechanical devices and systems, nanophotonics, and biosensors, such as white light-emitting diodes. The results from this research will help strengthen U.S. standing and influence in nanoelectronics, solar energy and nanophotonics. The interdisciplinary nature of this research will help the American workforce become more competitive in both materials processing and photonics through the training of graduate and undergraduate students. These students will master the synthesis and characterization skills of semiconductor nanocrystals and will develop the skills for solving technical problems. The investigator will actively recruit women and underrepresented minorities in order to promote their inclusion in the fields of nanophotonics and biophotonics.Semiconductor nanocrystals as potential building blocks of nanophotonics and biophotonics have attracted great interest in a variety of applications. The comprehensive understanding of the effects of the geometric dimensions and thermal-opto-mechanical interactions on the optical characteristics of the multilayer semiconductor nanocrystals can help develop better performing and more reliable nanocrystal-devices and systems. This research project will investigate the optical characteristics of the multilayer semiconductor nanocrystals under thermomechanical loading, including tension, compression and cyclic heating-cooling via a closely coupled experimental and modeling approach, and the dependence of the geometrical dimensions of the multilayer semiconductor nanocrystals on the precursor concentrations, temperature and residence time. A microreactor in a microfluidic system will be developed to synthesize the multilayer semiconductor nanocrystals and to investigate the rate mechanisms controlling the growth of the multilayer semiconductor nanocrystals in a flow environment. The research team will establish correlations between optical properties of the multilayer semiconductor nanocrystals, stress, and temperature as well as the geometrical dimensions. The team will develop numerical models that can quantitatively analyze optical responses of nanocrystals under thermomechanical loading. These relationships provide fundamental understanding of the thermal-opto-mechanical coupling in semiconductor nanocrystals and can provide guidelines to better design nanocrystal-based devices and systems with high performance and reliability. Students will be trained on the design of microfluidic reactors and the development of the techniques for local characterization of thermal-opto-mechanical behavior of semiconductor nanocrystals. A design project of developing microfluidic systems for chemical reactions will be developed and offered to high school and undergraduate students, from which students can learn both the technical and nontechnical requirements for the design of a useful product.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.