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

• Applicant: Professor Dr. Daniel M. Schaadt
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2008 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 74136017

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.

• DFG Programme: Research Grants
• International Connection: USA
• Participating Person: Professor Dr. Edward T. Yu