CAREER: Fundamental Physics and Device Issues of Novel GaAs Thermophotovoltaic Cells

大量的民用和军用企业对热光伏(TPV)发电表现出浓厚的兴趣，因为它是一种有吸引力的、清洁、高效和廉价的替代能源。TPV热源的低功率(约1400℃)使TPV电池最常用的材料是锑化镓(GASB)，而不是硅。GASB TPV电池的研究目前主要集中在：(1)提高TPV效率；(2)降低生产成本。本文提出了首次将砷化镓(GaAs)作为TPV电池的可行材料的研究。有两个令人信服的原因。首先，在GaAs衬底上制造TPV电池可以利用现有的GaAs设施，以低成本、高成品率、大批量生产与大型六英寸衬底上的GaAs集成电路(IC)兼容的TPV电池。其次，我们创新的TPV电池可以设计成特别高的效率，因为它们在同一个GaAs衬底上同时响应近红外(小于1.5微米)和中红外(2-5微米)。这项建议开发了三种使能在GaAs上制造高效率TPV电池的技术：(1)创新的子带间TPV器件设计，用于宽带热源的高功率转换效率；(2)新型低温生长(LTG)GaAs，设计用于1.5微米波长(一个重要的TPV波长)的强吸收；(3)高掺杂(10^{20}cm-3})接触和连接串联TPV电池的高掺杂隧道结的生长和退火。这项拟议的工作非常适合学术环境，因为它具有跨学科的性质，强调：理论和实验；吸收、传输和材料的基础研究；以及创新的TPV细胞。一项创新是子带间串联TPV(ITTPV)单元的拟议设计，其预计转换效率(35%)远远高于现有设备的转换效率(6%)。拟议的LTG-GaAs研究超越了以前的工作，因为它强调了1.5微米处更强的吸收的物理和工程方面的研究。关于高掺杂TPV隧道结和接触的拟议工作强调：开发掺杂限制的物理模型；以及比最先进的能力快得多的新型热退火(毫秒而不是几秒)。PI的教育计划有三个组成部分：(1)新课程开发，(2)指导活动，(3)参与研究研讨会。

TNumerous civilian and military ventures are showing keen interest in the thermo photovoltaic (TPV) generation of electricity as an attractive, clean, efficient, and inexpensive alternative energy. The low power (about 1400 C) of TPV heat sources makes gallium antimonide (GaSb), rather than silicon, the most common material for TPV cells. Research on GaSb TPV cells is currently focused on: (1) increasing the TPV efficiency, and (2) reducing the cost of production. This document proposes the first study of gallium arsenide (GaAs) as a viable material for TPV cells. There are two compelling reasons. First, the manufacture of TPV cells on a GaAs substrate could take advantage of existing GaAs facilities for low-cost, high-yield, large-volume production compatible with GaAs integrated circuits (ICs) on large six-inch substrates. Second, our innovative TPV cells can be designed for exceptionally high efficiency because of theirsimultaneous response, on the same GaAs substrate, to both the near infrared (less than 1.5micron) and the mid-infrared (2-5micron).This proposal develops three enabling technologies for making high efficiency TPV cells on GaAs: (1) innovative design of intersubband TPV devices for high power conversion efficiency of broadband heat sources; (2) novel Low-Temperature Grown (LTG) GaAs designed for strong absorption at the 1.5micron wavelength (an important TPV wavelength); (3) growth and annealing of very highly doped (10^{20}cm^{-3}) contacts, and highly doped tunnel junctions connecting series-TPV cells. This proposed work is ideally suited for an academic environment because of its interdisciplinary nature, emphasizing: both theory and experiment; fundamental studies of absorption, transport, and materials; and innovative TPV cells. One innovation is the proposed design of Intersubband Tandem TPV (ITTPV) cells, which have projected conversion efficiencies (35%) much higher than those (6%) of existing devices. The proposed study of LTG-GaAs goes beyond previous work in that it emphasizes the physics and engineering of a much stronger absorption at 1.5micron. The proposed work on very highly doped TPV tunnel junctions and contacts emphasizes: developing physical models of doping limitations; and a novel thermal anneal much more rapid (milliseconds instead of seconds) than the state-of-the-art capability. PI's educational program has three components: (1) new curriculum development, (2) mentoring activities, and (3) participation in research seminars.