Molecular Monolayers on CMOS for Nanoscale Chemical Sensors

该项目将集中于制备和表征的可极化分子单层设计成CMOS电路的光学和化学传感，与化学和生物化学，电气工程，和固态电子研究中心在亚利桑那州州立大学的部门合作。 所提出的基于FET的化学传感器的活性部分将是一个分子系统，可以在不同的偏振状态之间切换。 与每个状态相关的不同偶极场将导致阈值电压的差异，这可以通过电学方法测量。 分子物种将通过自组装附着到分裂栅SOI MOSFET的栅氧化层上。 我们的小组将制造单分子膜，并使用扫描探针显微镜技术- STM，AFM和导电尖端AFM -在受控环境下，如真空或干燥氮气对其进行表征。 这些仪器将使人们有可能更好地了解表面单分子层的分子构型。 在分子单层被极化之前和之后的表面电势将由数值模拟确定，该表面电势又可以与分子的偶极场相关，并且与由CT-AFM测量确定的物理结构相关。 通过将表面电位的测量与结构信息和分子建模相结合，我们将能够深入了解分子单层如何在氧化硅衬底上自组装，以及极化后它们的电子构型如何变化。 将分子的物理结构与其相关的偶极场相关联的能力是我们提出的混合分子-半导体异质结的独特特征。 化学，物理和电气工程的混合将为研究生和本科生提供在真正的跨学科环境中工作的机会。

The project will concentrate on the preparation and characterization of polarizable molecular monolayers designed into CMOS circuitry for optical and chemical sensing, in collaboration with the Departments of Chemistry and Biochemistry, and Electrical Engineering, and the Center for Solid State Electronics Research at Arizona State University. The active part of the proposed FET-based chemical sensors will be a molecular system that will be switchable between different polarization states. The different dipole fields associated with each state would lead to a difference in threshold voltage that could me measured electrically. The molecular species will be attached to the gate oxide of a split-gate SOI MOSFET by self-assembly. Our group will fabricate the monolayers and characterize them using scanning probe microscopy techniques - STM, AFM, and conducting-tip AFM - under a controlled environment, such as vacuum or dry nitrogen. These instruments will make it possible to better understand the molecular configuration of the surface monolayer. The surface potential before and after the molecular monolayer is polarized will be determined from numerical simulations this surface potential can in turn be related to the dipole filed of the molecule and correlated with the physical structure as determined by the CT-AFM measurements. By combining the measurements of the surface potential with structural information and molecular modeling we will be able to develop a thorough understanding of how the molecular monolayers self-assemble on oxidized silicon substrates, and how their electronic configuration changes after polarization. The ability to correlate the physical structure of the molecules with their associated dipole field is a unique feature of the hybrid molecular-semiconductor heterojunctions that we are proposing. The mix of chemistry, physics and electrical engineering will provide opportunities for graduate and undergraduate students to work in a truly interdisciplinary environment.