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

这个小企业创新研究（SBIR）二期项目的目标是生产用于TPV使用的多电池（MIM）结构的GaSb光伏设备。目前的设备使用单个电池。MIM器件在效率和成本上都比单电池具有显著的优势。MIM器件由物理隔离在同一衬底上的许多子单元组成。这按比例增加输出电压和减少输出电流，从而降低内部功率损耗。到目前为止，还没有出版物描述MIM Ge或GaSb MIM设备。第一阶段计划证明了高寿命的GaSb可以在半绝缘的GaAs上外延生长，而IR&amp；D计划证明了50个亚电池MIM器件可以在半绝缘的GaAs上由外延锗制造。把这些元素结合起来，就会产生一种理想的装置。尽管Ge MiM适用于冠捷，但GaSb MiM将使性能提高3到10倍。该项目更广泛的影响/商业潜力是经济有效地将余热转化为电能。在美国，57%的发电被当作废热来处理，然而，到目前为止，还没有成功的尝试将这些热量转化为电能，而不是蒸汽来加热。MTPV正在开发一种热光伏解决方案来解决这个问题，并且是使用近场倏逝耦合的先驱，可以在给定温度下显着增加从热源获得的功率密度。MTPV已经发表了一篇关于这一现象的明确论证，并正在将其商业化使用。设计用于从热源传递能量的硅发射极芯片以这种方式促进亚微米间隙的形成，目前正在铸造厂以及单电池和MIM Ge器件中生产。包含这些芯片并允许插入1100摄氏度熔炉所需的独特外壳是在MTPV设计/制造的。进行发电试验的设施。

This Small Business Innovation Research (SBIR) Phase II Project goal is to produce GaSb photovoltaic devices of multicell (MIM) construction for TPV use. Current devices use single cell. MIM devices have significant advantages over single cell in efficiency and cost. A MIM device is composed of many sub-cells physically isolated on the same substrate. This proportionally increases output voltage and decreases output current resulting in lower internal power loss. To date there have been no publications describing MIM Ge or GaSb MIM devices. The Phase I Program demonstrated that high lifetime GaSb can be epitaxially grown on semi insulating GaAs and an IR&D program demonstrated that 50 subcell MIM devices can be fabricated from epitaxial germanium on semi insulating GaAs. Combining these elements will produce an ideal device. Although the Ge MiM is suitable for TPV a GaSb MIM would give a three to tenfold improvement in performance.The broader impact/commercial potential of this project is to economically & efficiently recover waste heat as electricity. 57% of all power generated in the US is rejected as waste heat, however, to date there have been no successful attempts to recover this heat as electricity as opposed to steam for heating purposes. MTPV is developing a thermophotovoltaic solution to address this problem and is a pioneer in the use of near-field evanescent coupling to dramatically increase the power density obtainable from a heat source at a given temperature. MTPV has published a clear demonstration of this phenomenon and is engaged in commercializing its use. Silicon emitter chips designed to transfer energy from a heat source in such a manner as to facilitate the formation of a sub-micron gap are currently being produced in a foundry as well as both single cell and MIM Ge devices. The unique housing that is required to contain these chips and allow insertion into an 1100 degree C furnace is designed/ fabricated at MTPV?s facility where power generation tests are conducted.