Photoconductive Metal Nanowires with Embedded Semiconductor Nanonodes

技术描述：正在研究一种新的策略来制造纳米级光导体，这种光导体在光导状态对光(100 Ns)的响应和恢复方面是快速的，并且对光高度敏感，具有高的内部光导增益(100)。增益被定义为每个被吸收的光子产生的电子的数量，可以通过将半导体纳米线的长度折叠，直到它成为夹在一对金属电触点之间的半导体纳米颗粒来最大化。这种排列是通过制备交叉纳米线阵列来实现的，在交叉纳米线阵列中，例如，在两条金纳米线之间夹有超薄(100 Nm)的硒化镉光吸收层。除了一组金属纳米线被p型半导体纳米线取代外，使用相同的交叉纳米线策略获得发光结或纳米节点，例如银(I)氧化物或PEDOT(聚(3，4-乙烯二氧基噻吩基))。由此形成光电发射的n-p结。用于制备用作光导光学传感器和光电发射结的交叉纳米线结的密集阵列的方法正在开发中。这些结构的基本方面正在使用单交叉纳米线结进行探测。将描述用于检测空间调制光源的光导阵列的特性以及用于产生空间调制光的光电发射阵列的集体特性。非技术描述：正在研究一种制造小于光波长的光学探测器和光源的新方法。在这个项目中，由金属或半导体组成的纳米线的线性阵列相互叠加，形成一个纳米线交叉或连接的阵列。这种交叉纳米线策略应该能够产生数百万个光学探测器或光源的阵列。该项目为研究生提供多学科的培训经验，包括纳米制造、表面化学、电化学、凝聚态物理和光谱学。与这些研究活动并行的是一项以奖学金为基础的外展计划，目标是经济困难的高中生。

Technical Description: A new strategy is under investigation for the creation of nanometer-scale photoconductors that are both fast, in terms of the response and recovery of the photoconductive state to light (100 ns), and highly sensitive to light, possessing a high internal photoconductive gain (100). The gain, defined as the number of electrons produced for each absorbed photon, can be maximized by collapsing a semiconductor nanowire in length until it becomes a semiconductor nanoparticle, cradled between a pair of metal electrical contacts. This arrangement is achieved by preparing arrays of crossed nanowires in which an ultrathin (100 nm) optical absorbing layer of cadmium selenide, for example, is sandwiched between two gold nanowires. Light-emitting junctions or nanonodes are obtained using the same crossed-nanowire strategy except that one set of metal nanowires is replaced by p-type semiconductor nanowires, such as silver (I) oxide or PEDOT (poly (3,4-ethylene-dioxythiophene)). A photoemissive n-p junction is thereby formed. Processes for preparing dense arrays of crossed nanowire junctions that function as photoconductive optical sensors and photoemissive junctions are being developed. Fundamental aspects of these structures are being probed using single crossed nanowire junctions. The properties of photoconductive arrays for detecting spatially modulated light sources, and the collective properties of photoemissive arrays for generating spatially modulated light will be characterized. Non-technical Description: A new method is being studied for fabricating optical detectors and light sources that are smaller than the wavelength of light. In this project, linear arrays of nanowires composed of metal or semiconductors are superimposed on top of one another to create an array of nanowire crossings or junctions. This crossed nanowire strategy should be capable of producing arrays of millions of optical detectors or optical sources. This project provides a multidisciplinary training experience for graduate students that encompassing nanofabrication, surface chemistry, electrochemistry, condensed matter physics, and spectroscopy. A fellowship-based outreach program that targets economically disadvantaged high-school students is operating in parallel with these research activities.