SBIR Phase I: Epitaxially Grown GaSb Thin Films on GaAs Substrates For Near-Field Conversion of Heat to Electricity

该小型企业创新研究(SBIR)第一阶段项目旨在开发用于近场热光伏(TPV)器件的直接在GaAs上生长的无应变GaSb薄膜。直接低禁带材料的薄膜将在功率密度和效率方面超过间接带隙材料Ge。在本项目中，TPV器件将使用分子束外延(MBE)直接在GaAs上生长的GaSb薄膜在近场中制造和测试。结果表明，异质结处良好的90度失配位错导致在相对便宜的GaAs衬底上生长出应变消除的、低缺陷密度的GaSb薄膜。这些衬底还具有制造单片集成TPV器件所需的光学和电学特性，这些器件与热辐射器的近场操作兼容。该项目的更广泛/商业影响将是在废热收集方面提供经济上可行的解决方案的潜力。在世界上生产的所有电力中，超过一半是以余热的形式被丢弃的。这导致世界各地的研究团队都在寻找废热回收的固态解决方案，但成功非常有限。该项目将开发TPV设备，并证明它们在热物体的近场运行可能导致功率密度比现有技术增加10倍以上。这项技术有望用于工业余热、甲烷燃烧、太阳能、车辆电力、卫星电力和个人便携式电力应用。

This Small Business Innovation Research (SBIR) Phase I project aims to develop strain-relieved GaSb thin films grown directly on GaAs for near-field thermophotovoltaic (TPV) devices. Thin films of direct low-bandgap materials will outperform germanium, an indirect bandgap material, in both power density and efficiency. In this project, TPV devices will be fabricated and tested in the near-field using thin films of GaSb grown directly on GaAs via molecular beam epitaxy (MBE). It has been shown that the well-behaved 90-degree misfit dislocations at the heterojunction result in strain-relieved, low defect density thin films of GaSb grown on relatively inexpensive GaAs substrates. These substrates also have the optical and electrical properties required for fabrication of monolithically integrated TPV devices that are compatible with operation in the near-field of a hot thermal radiator.The broader/commercial impact of this project will be the potential to provide an economically viable solution in waste heat harvesting. Of all power produced in the world, over half is rejected in the form of waste heat. This has led research teams worldwide to search for solid state solutions to waste heat recovery, but with very limited success. This project will develop the TPV devices, and demonstrate that their operation in the near field of hot objects may lead to more than a tenfold increase in power density over existing technologies. This technology is expected to be used for industrial waste heat, methane flaring, solar, vehicle power, satellite power, and personal portable power applications.