Electronic properties of chemically modified surfaces and nanostructured materials

这项研究计划的目标是通过化学修饰来调整表面和纳米材料的电子特性。极性分子在表面的吸附或共价附着可导致材料功函数的巨大变化。此外，在半导体表面上，由于表面电荷产生的电场的渗透，这些修饰可以对电子特性产生长期（10-1000nm）的影响，这些电场会改变能级并影响自由载流子的密度（一种通常称为能带弯曲的现象）。这些效应可以用于化学和生物化学物质的电检测，也可以用于晶体管、光伏和发光二极管等电子设备的设计。在提出的工作中，我们将继续学习如何使用化学改性来诱导带弯曲和控制硅上的电输运。具有供电子和吸电子特征的有机官能团的表面功能化将用于系统地改变电导率并形成选择性响应不同分子种类的表面。学习如何控制和利用这些效应将在化学和生化检测以及开发纳米级导电通道形成的新方法中被证明是有用的。对平面硅的研究将扩展到硅纳米线网络和单个硅纳米线。纳米线对吸附和反应事件的敏感性将与平面衬底进行比较。

The goal of this research program is the development of methods for tuning the electronic properties of surfaces and nanomaterials via chemical modification. Adsorption or covalent attachment of polar molecules at a surface can lead to large changes in the work function of the material. In addition, on semiconductor surfaces, these modifications can have long-range (10-1000nm) effects on the electronic properties due to the penetration of electric fields arising from surface charges which shift energy levels and influence the density of free carriers (a phenomena often called band-bending). These effects can be exploited for electrical detection of chemical and biochemical species as well as in the design of electronic devices such as transistors, photovoltaics, and light emitting diodes. In the proposed work we will continue to learn how chemical modification can be used to induce band bending and control electrical transport on silicon. Functionalization of the surface with organic functional groups of electron donating and withdrawing character will be used to systematically alter the conductivity and form surfaces that selectively respond to different molecular species. Learning how to control and exploit these effects should prove useful in chemical and biochemical detection as well as in the development of a new approach to the formation of nanoscale conducting channels. Studies on planar silicon will be extended to silicon nanowire networks and individual silicon nanowires. Sensitivity of nanowires to adsorption and reaction events will be compared with the planar substrates.