NASA Scientific and Technical Aerospace Reports

13.4% on a non-textured single-sided heterojunction solar cell on p-type CZ-Si processed with optimized surface treatment.
NTIS
Crystal Surfaces; Crystals; Heterojunction Devices; Passivity; Silicon; Solar Cells; Vapor Deposition
20060002209 National Renewable Energy Lab., Golden, CO USA
Relationship of Recombination Lifetime and Dark Current In Silicon p-n Junctions
Ahrenkiel, R. K.; Metzger, W.; Page, M.; Reedy, R.; Feb. 2005; 12 pp.; In English
Report No.(s): DE2005-15016492; NREL/CP-520-37438; No Copyright; Avail.: National Technical Information Service
(NTIS)
Measurement of recombination and minority-carrier lifetimes has become a central activity in photovoltaic technology.
The primary measurement techniques for silicon technologies are based on photoconductive decay (PCD) and microwave
reflectance (mPCD). The measurement of the correct recombination lifetime depends on the carriers being confined to a given
spatial region of a diagnostic structure. The internal electric fields separate the charges, and the measured value does not
represent the real minority-carrier lifetime. In these cases, the measured quantity is a function of the true lifetime and the
sample structure. Here, we examine these effects, both experimentally and theoretically, for the n(sup +)-p device structure
common to terrestrial photovoltaics.
NTIS
Dark Current; P-N Junctions; Silicon; Silicon Junctions
20060002210 National Renewable Energy Lab., Golden, CO USA
Comprehensive Model of Hydrogen Transport into a Solar Cell During Silicon Nitride Processing for Fire-Through
Metallization
Sopori, B.; Reedy, R.; Jones, K.; Al-Jassim, M.; Aug. 2004; 12 pp.; In English
Report No.(s): DE2005-15016499; NREL/CP-520-37477; No Copyright; Avail.: National Technical Information Service
(NTIS)
A mechanism for the transport of H into a Si solar cell during plasma-enhanced chemical vapor deposition (PECVD) of
a hydrogenated silicon nitride (SiN:H) layer and its subsequent fire-through metallization process is described. The PECVD
process generates process-induced traps, which ‘’store’’ H at the surface of the solar cell. This stored H is released and diffuses
rapidly into the bulk of Si during the high-temperature metallization-firing process. During the ramp-down, the diffused H
associates with impurities and defects and passivates them. The firing step partially heals up the surface damage. The proposed
model explains a variety of observations and experimental results.
NTIS
Fires; Hydrogen; Metallizing; Silicon Nitrides; Solar Cells
20060002211 National Renewable Energy Lab., Golden, CO USA
Effective Interfaces in Silicon Heterojunction Solar Cells
Wang, T. H.; Iwaniczko, E.; Page, M. R.; Levi, D. H.; Feb. 2005; 12 pp.; In English
Report No.(s): DE2005-15016495; NREL/CP-37457; No Copyright; Avail.: National Technical Information Service (NTIS)
This paper reviews the current commercial status of CuInSe2 alloys (collectively, CIS) and CdTe-based photovoltaic (PV)
modules, comparing the performance of commercial products with the results achieved for solar cell and prototype module
champions. We provide an update for these PV cell and module technologies, and also compare CIS and CdTe performance
levels to the results achieved by the crystalline Si PV industry. This comparison shows that CIS and CdTe module technology
presently offers the best (and perhaps only) approach for significantly exceeding the cost/performance levels established by
crystalline Si PV technologies. A semi-empirical methodology is used for comparing ‘’champion’’ solar cell and prototype
module data with performance achieved on manufacturing lines. Using a conservative assumption that thin-film technologies
will eliminate the 40% of PV module costs arising from the Si wafer or ribbon, we estimate the future performance of all
established PV module candidates, and conclude that, based on 2004 knowledge about each PV technology, CIS and CdTe
should provide cost-competitive advantages over crystalline Si.
NTIS
Heterojunction Devices; Heterojunctions; Silicon; Solar Cells
20060002212 National Renewable Energy Lab., Golden, CO USA
Enhanced-Depletion-Width GalnNAs Solar Cells Grown by Molecular-Beam Epitaxy
Ptak, A. J.; Friedman, D. J.; Kurtz, S.; Kiehl, J.; Feb. 2005; 12 pp.; In English
Report No.(s): DE2005-15016500; NREL/CP-520-37479; No Copyright; Avail.: Department of Energy Information Bridge
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