Materials World Network: Quantum Semiconductor Structures for High-Efficiency Photovoltaics

本项目致力于用于高效率光伏器件的GaAs/GaInAs/GaInNAs量子阱和量子点p-i-n异质结材料的合成、加工和表征。在光伏器件的背景下，探索了优化外延异质结界面质量和通过分子束外延控制自组装量子点结构形成的基本问题，但具有广泛的材料和器件含义。此外，还考察了量子井/点和相关光伏器件概念的基本物理和性能潜力，并将其用作探索特定材料问题的驱动因素。还研究了金属和介电纳米结构与半导体异质结构的集成，这有望在半导体异质结构中光子传播行为的工程化方面取得重大进展。最终，预计该项目在材料物理方面的进步将大大促进高效量子井和量子点太阳能电池的发展，理论上预测，这种电池的电力转换效率将远远超过使用更传统的太阳能电池技术所能达到的效率。这项工作需要加州大学圣地亚哥分校(UCSD)和德国卡尔斯鲁厄大学的研究人员进行国际合作。在Daniel Schaadt博士的领导下，卡尔斯鲁厄大学的研究人员专注于外延材料的生长和优化，而加州大学圣迭戈分校的研究人员则专注于材料加工、表征以及最终整合到光伏器件结构中。材料世界网络项目促进了美国和德国的研究人员之间的合作，预计将为处于不同文化和科学环境中的研究生和博士后研究人员提供宝贵的经验，并有助于促进未来在太阳能和固态纳米结构领域快速增长的研究和商业活动之间的国际合作和联系。鉴于德国对太阳能技术的坚定承诺和在其中的活动，它是这方面特别合适的伙伴。该项目产生的材料进步可能带来的高效太阳能转换的技术和经济影响可能是巨大的。此外，该项目利用了与每个机构的主要研究中心相关的设施和专业知识。加州大学圣迭戈分校的加州电信和信息技术研究所(Calit2)和卡尔斯鲁厄的DFG功能纳米结构中心(CFN)。访问卡尔斯鲁厄的UCSD研究人员受益于材料合成和表征的广泛设施，以及接触到CFN在电子、光子学和生物学方面的纳米结构材料的广泛研究。访问加州大学圣迭戈分校的卡尔斯鲁厄大学的研究人员可以接触到广泛的多学科研究环境，从事电信和信息技术的基础材料、设备和系统方面的问题，并将受益于Calit2最先进的实验材料加工和纳米制造设施。

This project is directed toward the synthesis, processing, and characterization of GaAs/GaInAs/GaInNAs quantum-well and quantum-dot p-i-n heterostructure materials for application in high-efficiency photovoltaic devices. Fundamental issues in optimization of epitaxial heterojunction interface quality and controlled formation of self-assembled quantum dot structures by molecular-beam epitaxy are explored in the context of photovoltaic devices but with broad-ranging material and device implications. In addition, the basic physics and performance potential of quantum-well/dot and related photovoltaic device concepts is examined and employed as a driver for exploration of specific materials issues. Integration of metal and dielectric nanostructures with semiconductor heterostructures, which is expected to enable key advances in engineering of photon propagation behavior in semiconductor heterostructures, is also investigated. Ultimately, it is anticipated that the advances in materials physics enabled by the project will contribute substantially to the development of highly efficient quantum-well and quantum-dot based solar cells, which have been predicted theoretically to enable power conversion efficiencies well in excess of those attainable using more conventional solar cell technologies. This work entails an international collaborative effort between researchers at the University of California, San Diego (UCSD) and at the University of Karlsruhe in Germany. Researchers at Karlsruhe, led by Dr. Daniel Schaadt, focus on epitaxial material growth and optimization, while UCSD researchers focus on materials processing, characterization, and eventual incorporation into photovoltaic device structures. This Materials World Network project enables collaboration between researchers in the Unites States and Germany that is expected to provide invaluable experience for graduate student and postdoctoral researchers in different cultural and scientific environments, and to help seed future international collaborations and connections between rapidly growing research and commercial activities in solar energy and solid-state nanostructures generally. Germany is a particularly appropriate partner in this regard, in light of its strong commitment to and activity in solar energy technologies. The technological and economic impact of high-efficiency solar energy conversion that could be enabled by the materials advances emerging from this project is potentially dramatic. In addition, the project makes use of facilities and expertise associated with major research centers at each institution ? the California Institute for Telecommunications and Information Technology (CalIT2) at UCSD and the DFG-Center for Functional Nanostructures (CFN) at Karlsruhe. UCSD researchers visiting Karlsruhe benefit from the availability of extensive facilities for materials synthesis and characterization, and from exposure to the broad range of research at CFN on nanostructured materials for electronics, photonics, and biology. Researchers from Karlsruhe visiting UCSD gain exposure to the broad, multidisciplinary research environment that engages issues in basic materials, devices, and systems for telecommunications and information technology, and will benefit from the availability of state-of-the-art experimental materials processing and nanofabrication facilities at CalIT2.