Materials World Network: Design, fabrication and characterization of advanced heterojunction photovoltaic devices based on enhanced scattering into lateral optical paths

我们建议加州大学圣地亚哥分校（E. Yu， PI）和德国卡尔斯鲁厄大学（D. Schaadt）进行国际合作，开发用于高效光伏器件的GaAs/InGaAs和GaAs/InGaNAs量子阱（QW）和量子点（QD） p-i-n异质结构。首先，实现功率转换效率超过60%；p-i-n光电二极管本征区的量子阱层和量子点层将用于吸收太阳光谱中低于GaAs p和n电极层带隙能量的入射光子。其次，通过集成金属或介电纳米结构，将量子阱/点波长的入射光子散射到横向传播路径中，从而实现薄多重QW和/或QD层的高效吸收。由于InGaAs相对于GaAs具有更高的折射率，横向传播路径受到光学限制。研究最终将通过衬底去除和双面加工开发出非常薄的器件结构。这种结构将为入射光子提供非常有效的耦合，使其进入侧向光学受限的传播路径，并能够在柔性或弯曲的表面上进行键合。在这项合作中，卡尔斯鲁厄大学的研究人员将专注于材料的生长和优化，而加州大学圣地亚哥分校的研究人员将专注于设备的设计、加工和表征。

We propose an international collaborative effort between the University of California, San Diego (E. Yu, PI) and the University of Karlsruhe in Germany (D. Schaadt) to develop GaAs/InGaAs and GaAs/InGaNAs quantum-well (QW) and quantum-dot (QD) p-i-n heterostructures for high-efficiency photovoltaic devices First, to achieve power conversion efficiencies in excess of 60%, quantum-well and quantum-dot layers in the intrinsic region of a p-i-n photodiode will be used for absorption of incident photons in the solar spectrum at energies below the band gap of the GaAs p and n electrode layers. Second, highly efficient absorption in thin multiple QW and/or QD layers will be achieved by integration of metal or dielectric nanostructures to scatter incident photons at quantum-well/dot wavelengths into lateral propagation paths that are optically confined due to the higher refractive index of InGaAs relative to GaAs. Research will culminate in the development of a very thin device structure via substrate removal and double-sided processing. This structure will provide very efficient coupling of incident photons into lateral optically confined propagation paths, and enable bonding onto flexible or curved surfaces. In this collaborative effort, researchers at Karlsruhe will focus on material growth and optimization, while UCSD researchers will focus on device design, processing, and characterization.