STTR Phase I: High Efficiency Thin-film Photovoltaics on Low-cost Substrates by Layer Transfer

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。这个小企业技术转移一期项目将采用高纵横比、纳米级、柱状和晶体硅结构作为模板，在低成本的柔性衬底上高质量地生长薄膜砷化镓太阳能电池。10纳米以下的Si种子层有望促进低缺陷密度GaAs薄膜的生长。纳米尺度结构的纵横比也可以作为去除完整的砷化镓太阳能电池的牺牲层。纳米级硅结构上GaAs薄膜的外延生长和表征将在新墨西哥大学的高科技中心进行。第一阶段STTR研究的成功将导致高（~ 20%）效率的商业化，灵活的太阳能电池应用于广泛的地面和空间环境。多重衬底再利用和Si的大面积加工能力将显著降低成本。在硅上生长高质量的异质外延砷化镓一直是人们研究的热点。由于其直接带隙，GaAs对许多光电子应用具有吸引力，其与硅基微电子的集成一直是一个珍贵的目标。与硅的晶格和热膨胀不匹配使其难以生长出良好的器件质量层。我们最近已经证明，当Si种子尺寸减小到100纳米以下时，异质外延生长的质量迅速提高。纳米级硅结构是在传统集成电路加工方法的基础上，采用低成本、大面积的方法形成的。成功的研究工作将导致光伏发电成本的降低，并增强薄膜光伏在地面和空间环境中的适用性，因为与竞争的薄膜太阳能电池相比，GaAs薄膜太阳能电池不会受到光致性能下降的影响。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This Small Business Technology Transfer Phase I project will apply high aspect ratio, nm-scale, columnar, and crystalline Si structures as templates for high-quality growth of thin-film GaAs solar cells on low-cost flexible substrates. Sub-10-nm Si seed layers are expected to facilitate growth of low-defect density GaAs films. The aspect ratio of nm-scale structures also serve as sacrificial layers for removal of completed GaAs solar cell. Epitaxial growth and characterization of GaAs films on nm-scale Si structures will be carried out at the Center for High Technology at the University of New Mexico. Successful phase I STTR research will lead to commercialization of high (~ 20 %) efficient, flexible solar cells for applications in a wide range of terrestrial and space environments. Multiple substrate re-use and inherent large area processing capability of Si will result in significant cost reductions.High quality heteroepitaxial GaAs growth on Si has been a subject of intense research. Due to its direct bandgap, GaAs is attractive for a number of optoelectronics applications and its integration with Si-based microelectronics has been a cherished goal. The lattice and thermal expansion mismatches with Si make it difficult to grow good device quality layers. We have recently demonstrated as the Si seed dimension is reduced below 100 nm dimensions, the quality of heteroepitaxial growth increases rapidly. The nm-scale Si structures are formed using low-cost, large area methods based on conventional integrated circuit processing methods. Successful research effort will lead to reduction in PV generation costs, and enhanced applicability of thin-film PV in terrestrial and space environments because in contrast with competing thin-film solar cells, GaAs thin-film solar cells will not suffer from light-induced performance degradation.