SI/SIGE NANOWIRE ARRAYS FOR THERMOELECTRICITY

近年来，社会经济发展对化石燃料的日益依赖已成为一个令人高度关切的问题。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。这些替代方案中有许多是旧的想法，使用现代技术实现。该提案计划使用基于纳米技术的新方法，研究将众所周知的热电效应用作能源。热电利用温度梯度产生电流。这一基本物理原理自19世纪30年代以来就已为人所知。这种方法的优点是热电发电机没有移动部件，并且安静而坚固，可以在存在温度梯度的任何情况下使用，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电器（例如笔记本电脑）以及可以清除工厂中产生的热量的大型工业应用中。不幸的是，由于缺乏具有大品质因数的材料，使用这种技术的真实的突破受到阻碍。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品质因数的极大改善，从而产生高效的热电器件。利用纳米线的热电效应前景看好，但还没有完全令人信服。为了获得高的品质因数，需要材料中的低热导率和高电导率。必须通过高载流子浓度和迁移率来获得高电导率。在这项可行性研究中，我们将研究一种在纳米线中引入带电载流子的新方法，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.