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dc.contributor.advisorTonio Buonassisi.en_US
dc.contributor.authorMorishige, Ashley E. (Ashley Elizabeth)en_US
dc.contributor.otherMassachusetts Institute of Technology. Department of Mechanical Engineering.en_US
dc.date.accessioned2014-03-06T15:45:09Z
dc.date.available2014-03-06T15:45:09Z
dc.date.copyright2013en_US
dc.date.issued2013en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/85481
dc.descriptionThesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.en_US
dc.descriptionCataloged from PDF version of thesis.en_US
dc.descriptionIncludes bibliographical references (pages 67-71).en_US
dc.description.abstractCrystalline silicon solar cells are a proven renewable energy technology, but they have yet to reach low costs commensurate with subsidy-free, grid-scale adoption. To achieve the widespread adoption of photovoltaics, the cost per unit of electricity must be reduced by increasing solar cell efficiency. Parts per trillion concentrations of iron impurities in the silicon material can severely limit solar cell efficiency. Iron can be found in both precipitated and point defect form in silicon. Both forms are detrimental to final solar cell efficiency, but their negative impact can be mitigated during solar cell processing. In a standard solar cell process, the phosphorus diffusion step is the key opportunity to redistribute iron impurities because it is the step with the largest thermal budget. Phosphorus diffusion process optimization for solar cell material so far typically consists of one or more isothermal steps followed by a cooling step. Iron silicide precipitates can be dissolved at high temperatures, whereas at lower temperatures, interstitially dissolved iron is driven to the phosphorus-rich layer. Previous optimizations typically maximize minority carrier lifetime without constraining process time and device parameters. This thesis explores a novel phosphorus diffusion process in which there are no isothermal steps. The goal of this work is to demonstrate simultaneous maximization of minority-carrier lifetime, while maintaining high process throughput and steady emitter sheet resistance. Predictive simulation, electrical characterization techniques, and synchrotron-based X-ray fluorescence were combined to compare this new processing approach to standard solar cell processing. This continuously ramped temperature processing may be a promising approach for maximizing solar cell performance, maintaining reasonable manufacturing rates, and achieving a target sheet resistance.en_US
dc.description.statementofresponsibilityby Ashley E. Morishige.en_US
dc.format.extent71 pagesen_US
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582en_US
dc.subjectMechanical Engineering.en_US
dc.titleCo-optimizing silicon solar cell processing for efficiency and throughputen_US
dc.typeThesisen_US
dc.description.degreeS.M.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Mechanical Engineering.en_US
dc.identifier.oclc870971922en_US


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