NER: Optical Modulation by Field Gated Transparency

该提案是响应纳米尺度科学与工程计划，NSF 01-157， NER类别而收到的。本项目将探索利用场效应诱导电荷注入半导体单壁碳纳米管的可行性，以调节纳米管薄膜的光吸收强度。该方法结合并扩展了最近的研究结果：1)纳米管吸收带可以通过化学和电化学诱导的纳米管费米能级的移动来调制；2)最近在基于纳米管的场效应晶体管中取得的成功，这种晶体管依靠场门控来类似地移动纳米管费米能级。对于具有典型直径范围为~1.1 - 1.6 nm的块状纳米管样品，感兴趣的吸收带（半导体纳米管的V1到C1跃迁）跨越1.55 mm波长，在光纤通信中具有技术相关性。使用场效应进行调制将产生一个全电可寻址的设备，具有高预期的切换速度。该研究将涉及开发具有良好光学清晰度的电耦合纳米管薄膜，将这些薄膜集成到透明电极、场门控器件中，并探索化学掺杂和纳米管-纳米管筛选对器件功能的影响。该提案确定了一种影响光调制的基本新机制，如果成功，将鼓励进一步优化基于纳米管的实现以及开发替代材料和器件。为了与佛罗里达大学和国家科学基金会培养下一代科学家的使命保持一致，该项目将资助研究生和本科生的研究。历史上在科学领域代表性不足的群体将被特别鼓励参与。

This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NER. This program will explore the feasibility of using field effect induced charge injection into semiconducting, single wall carbon nanotubes to modulate the intensity of the optical absorption in thin, optically uniform films of nanotubes. The approach combines and extends recent results showing that 1) nanotube absorption bands can be modulated by chemically and electrochemically induced shifts of the nanotube Fermi levels and 2) recent successes in nanotube based field effect transistors which rely on field gating to similarly shift the nanotube Fermi level. For bulk nanotube samples possessing typical diameters ranging from ~1.1 - 1.6 nm the absorption band of interest (the V1 to C1 transition for the semiconducting nanotubes) straddles the 1.55 mm wavelength having technological relevance in fiber optic communications. Use of the field effect for modulation will result in an all electrically addressable device, with high anticipated switching speeds. The research will involve development of electrically coupled nanotube films having good optical clarity, the integration of these films into transparent electrode, field-gated devices, and the exploration of chemical doping and nanotube-nanotube screening effects on the function of the devices. The proposal identifies a fundamentally new mechanism for effecting optical modulation and, if successful, should encourage further work both in optimizing the nanotube based implementation as well as the development of alternative materials and devices. In keeping with the University of Florida and the NSF mission of training future generations of scientists the program will fund the research of both graduate and undergraduate students. Historically under-represented groups in science will be particularly encouraged to participate.