SI/SIGE NANOWIRE ARRAYS FOR THERMOELECTRICITY

近年来，社会经济发展对化石燃料的依赖日益加剧，引起了人们的极大关注。化石燃料供应减少的可能性，以及这些燃料对气候变化的影响，鼓励了对替代能源的研究。这些替代方案中的许多都是使用现代技术实现的旧想法。这项提案计划使用一种基于纳米技术的新方法来研究利用众所周知的热电效应作为能源。热电使用温度梯度来产生电流。这一基本的物理原理早在19世纪30年代就已为人所知。这种方法的优点是，热电发电机没有移动部件，而且静音和坚固，可以在任何存在温度梯度的情况下使用，可以通过适当的材料选择在不同的温度范围内使用，并且可以用于小型轻型设备(如笔记本电脑)以及工厂产生的热量可以被清除的大型工业应用。不幸的是，由于缺乏一种具有大质量系数的材料，使用这项技术的真正突破一直受到阻碍。然而，最近国际上对半导体纳米线的研究表明，这些结构的小尺寸可能会导致热电性能因数大大提高，从而产生高效的热电设备。使用纳米线的热电的理由是有希望的，但还不完全令人信服。为了获得高品质因数，材料中既需要较低的热导率，又需要较高的电导率。必须通过高载流子浓度和迁移率来获得高导电性。在这项可行性研究中，我们将研究一种新的方法，在纳米线中引入带电载流子，同时避免通常与更传统的技术相关的对迁移率的不利影响。

In recent years, the increasing dependence of society on fossil fuels for socio-economical development has become a cause of great concern. The possibility of a reduced availability of fossil fuels, and the effect of these fuels on climate change, have encouraged research into alternative energy sources. Many of these alternatives are old ideas, implemented using modern techniques. This proposal plans to investigate the use of the well-known thermoelectric effect as an energy source, using a novel approach based on nanotechnology.Thermoelectricity uses a temperature gradient to generate an electrical current. This fundamental physical principle has been known since the 1830s. The advantages of this approach are that thermoelectric generators have no moving parts and are silent and robust, can be used in any situation where there is a temperature gradient, can be used in different temperature ranges via an appropriate material choice, and can be used in small lightweight appliances (e.g. laptops) as well as in large industrial applications where heat generated in a factory can be scavenged. Unfortunately, a real breakthrough using this technique has been hindered by the lack of a material with a large figure of merit. Recent international research on semiconductor nanowires, however, suggests that the small-dimensions of these structures may lead to a greatly improved thermoelectric figure of merit, generating efficient thermoelectric devices. The case for thermoelectricity using nanowires is promising, but not yet fully convincing. In order to obtain a high figure of merit both a low thermal conductivity and a high electrical conductivity in the material is needed. A high electrical conductivity must be obtained via a high carrier concentration and mobility. In this feasibility study, we will study a novel approach for introducing charged carriers in the nanowire, whilst avoiding the detrimental effects on mobility normally associated with the more traditional techniques.