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Effects of Plasma Hydrogenation on Trapping Properties of Dislocations in Heteroepitaxial InP/GaAsIn previous work, we have demonstrated the effectiveness of a post-growth hydrogen plasma treatment for passivating the electrical activity of dislocations in metalorganic chemical vapor deposition (MOCVD) grown InP on GaAs substrates by a more than two order of magnitude reduction in deep level concentration and an improvement in reverse bias leakage current by a factor of approx. 20. These results make plasma hydrogenation an extremely promising technique for achieving high efficiency large area and light weight heteroepitaxial InP solar cells for space applications. In this work we investigate the carrier trapping process by dislocations in heteroepitaxial InP/GaAs and the role of hydrogen passivation on this process. It is shown that the charge trapping kinetics of dislocations after hydrogen passivation are significantly altered, approaching point defect-like behavior consistent with a transformation from a high concentration of dislocation-related defect bands within the InP bandgap to a low concentration of individual deep levels after hydrogen passivation. It is further shown that the "apparent" activation energies of dislocation related deep levels, before and after passivation, reduce by approx. 70 meV as DLTS fill pulse times are increased from 1 usec. to 1 msec. A model is proposed which explains these effects based on a reduction of Coulombic interaction between individual core sites along the dislocation cores by hydrogen incorporation. Knowledge of the trapping properties in these specific structures is important to develop optimum, low loss heteroepitaxial InP cells.
Document ID
20000032852
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Ringel, S. A.
(Ohio State Univ. Columbus, OH United States)
Chatterjee, B.
(Ohio State Univ. Columbus, OH United States)
Date Acquired
August 19, 2013
Publication Date
September 1, 1994
Publication Information
Publication: Proceedings of the 13th Space Photovoltaic Research and Technology Conference (SPRAT 13)
Subject Category
Solid-State Physics
Funding Number(s)
CONTRACT_GRANT: NAG1-1461
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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