Growth and Defect Characterization of Quantum Dot-Embedded III-V Semiconductors for Advanced Space Photovoltaics
Abstract
A number of different QD/host materials systems were investigated via molecular beam epitaxy (MBE), ranging from the well-known lattice-matched host materials InAs/GaAs, Ga0.50In0.50As/GaAs, InP/Ga0.51In0.49P, and even InAs/Ga0.51In0.49P (which has actually seen very little investigation) to metamorphic host materials systems that have not previously been studied Ga0.55In0.45As/GaAs0.90P0.10 and InP/ Ga0.56In0.44P. From these exploratory materials efforts, two main conclusions were made: (1) QD/host materials compatibility have a major impact on ease of controlling the morphology and quality of the heterogeneous system, and (2) the use of metamorphic substrates appears to provide, in addition to better control over the QD/host electronic structure by giving a choice of materials, an additional parameter for control over QD size and density beyond what misfit and deposition conditions can provide, which could be useful in the future development of intermediate band solar cell (IBSC) devices. Defect spectroscopy was also performed on OMVPE-grown InAs/GaAs QD-embedded solar cells. A large increase in mid-gap trap density surrounding the embedded QDs was found and points to a potentially important performance degradation mechanism, and provides a target for future comparisons with MBE-grown QD/host systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 15, 2014
- Accession Number
- ADA602072
Entities
People
- John P. Saving
- Steve Ringel
- Tyler J. Grassman
Organizations
- Ohio State University