CAREER: Modulation Nanospectroscopy for Characterization of Local Electronic Properties

在化学系化学测量和成像项目的支持下，北卡罗来纳州-查佩尔山大学的Joanna Atkin教授和她的团队正在设计可以更好地表征半导体器件性能的工具。 这些工具在原子和分子（纳米）长度尺度上探测半导体的结构和电子特性。 特别是，研究人员试图了解纳米级晶体结构以及故意或无意中掺入的杂质如何影响电子功能和器件性能。半导体被用作逻辑门的构建块，逻辑门是计算机微处理器数字电路设计的基础。 研究生，本科生和高中生有助于这一跨学科的研究，在建筑仪器，光谱学，纳米纤维和计算建模获得经验。该小组与Morehead天文馆和科学中心合作，开发演示光学，量子力学和纳米技术概念的演示，旨在向公众有效地传达这项研究的科学基础。Atkin博士的研究小组还与校园内现有的针对服务不足人群的外展计划合作，让高中生参与科学研究，并为追求STEM职业提供指导和资源。最后，建立了一个网站和指导网络，将经历健康和残疾挑战的研究人员聚集在一起，以提高STEM的多样性和包容性。光学技术是唯一敏感的电子和结构参数，但固有的衍射限制，因此一般探针平均行为的材料，是异质的顺序，晶界，和界面在纳米级。Atkin小组正在开发“调制纳米光谱学”-一种新的亚衍射极限技术，用于表征半导体材料和器件。具体来说，他们将基于原子力显微镜的光学显微镜与场和光学调制相结合，以揭示10 nm长度尺度上自由和束缚电荷载流子激发的信息。正在考虑无机和有机测试系统，涵盖了一系列的运输制度，以探索当地的结构导电性关系。准粒子激发，如激子和极化子正在其自然长度尺度上进行探测，以探索从飞秒到秒的时间尺度上的非平衡性质。这些技术可应用于了解各种电子和光子材料的功能，从2D异质结构器件到混合有机-无机光伏器件。该奖项反映了NSF的法定使命，并通过使用基金会的知识产权进行评估而被认为值得支持优点和更广泛的影响审查标准。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Joanna Atkin and her group at the University of North Carolina - Chapel Hill are devising tools that can better characterize the performance of semiconducting devices. These tools probe the semiconductor's structure and electronic properties on the atomic and molecular (nanometer) length scale. In particular, the researchers seek to understand how nanoscale crystal structure and the deliberate or inadvertent incorporation of impurities impact electronic function and device performance. Semiconductors are used as the building blocks of logic gates, which are fundamental in the design of digital circuits for computer microprocessors. Graduate, undergraduate, and high school students contribute to this interdisciplinary research, gaining experience in building instrumentation, optical spectroscopy, nanofabrication, and computational modeling. The group partners with the Morehead Planetarium and Science Center to develop demonstrations illustrating optical, quantum mechanical, and nanotechnological concepts, with an aim of effectively communicating the scientific underpinnings of this research to the general public. Dr. Atkin's research group also partners with existing outreach programs on campus that target underserved populations, to engage high schoolers in scientific research and provide mentorship and resources for pursuing a STEM career. Finally, a website and mentoring network is established to bring together researchers who experience health and disability challenges to improve diversity and inclusion in STEM. Optical techniques are uniquely sensitive to electronic and structural parameters, but are inherently diffraction-limited and therefore generally probe averaged behavior for materials that are heterogeneous in order, grain boundaries, and interfaces at the nanoscale. The Atkin group is developing "modulation nanospectroscopy" - a new sub-diffraction-limit technique for characterizing semiconducting materials and devices. Specifically, they are combining atomic force microscopy-based optical microscopy with field and optical modulation to reveal otherwise inaccessible information about free and bound charge carrier excitations on 10 nm length scales. Both inorganic and organic test systems are being considered, covering a range of transport regimes, in order to explore local structure-conductivity relations. Quasiparticle excitations such as excitons and polarons are being probed on their natural length scales, to explore non-equilibrium properties over timescales from femtoseconds to seconds. The techniques can be applied to understanding function in a wide variety of electronic and photonic materials, from 2D heterostructure devices to hybrid organic-inorganic photovoltaics.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.