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Calculation of dopant solubilities and phase diagrams of X–Pb–Se (X = Br, Na) limited to defects with localized charge

Bajaj, Saurabh and Wang, Heng and Doak, Jeff W. and Wolverton, Chris and Snyder, G. Jeffrey (2016) Calculation of dopant solubilities and phase diagrams of X–Pb–Se (X = Br, Na) limited to defects with localized charge. Journal of Materials Chemistry C, 4 (9). pp. 1769-1775. ISSN 2050-7526. https://resolver.caltech.edu/CaltechAUTHORS:20160222-101712009

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Abstract

The control of defects, particularly impurities, to tune the concentrations of electrons and holes is of utmost importance in the use of semiconductor materials. To estimate the amount of dopant that can be added to a semiconductor without precipitating secondary phases, a detailed phase diagram is needed. The ability of ab initio computational methods to predict defect stability can greatly accelerate the discovery of new semiconductors by calculating phase diagrams when time-consuming experimental ones are not available. DFT defect energy calculations are particularly successful in identifying doping strategies by determining the energy of multiple defect charge states in large band gap semiconductors and insulators. In metals, detailed phase diagrams can be determined from such calculations but only one, uncharged defect is needed. In this work, we have calculated dopant solubilities of Br and Na in the thermoelectric material PbSe by mapping its solvus boundaries in different regions of the respective ternary phase diagrams using DFT defect energy calculations. The narrow gap PbSe provides an example where defects with nominal charge state (based on valence counting) have properly-localized charge states. However, defects with unexpected charge states produce delocalized electrons, which are then, in effect, defects with the expected charge state. Simply applying the methods for calculating multiple defect charge states in PbSe and treating them as separate defects fails to predict properties measured by experiments. Performing thermodynamic calculations using only the expected charge states, excluding others, enables accurate prediction of experimentally measured doping efficiencies and phase diagrams. Identifying which defect charge states to include in thermodynamic calculations will expedite the use of such calculations for other semiconductors in understanding phase diagrams and devising effective doping strategies.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/C5TC03970C DOIArticle
http://pubs.rsc.org/en/content/articlelanding/2016/tc/c5tc03970cPublisherArticle
ORCID:
AuthorORCID
Bajaj, Saurabh0000-0003-0216-9697
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2016 The Royal Society of Chemistry. Received 25th November 2015, Accepted 8th February 2016. First published online 09 Feb 2016. This article is part of themed collection: 2016 Journal of Materials Chemistry C Hot Papers. This work was supported by the Department of Energy's Basic Energy Sciences program – the Materials Project – under Grant No. EDCBEE. Work at Lawrence Berkeley, through discussions with Qimin Yan, Mark Asta, and Jeff Neaton, was supported by the Office of Science of the U.S. Department of Energy under Contract No. DEAC02-05CH11231. J. W. D. and C.W. acknowledge support by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Grant DEFG02-07ER46433. The authors acknowledge the Chemical Engineering Cluster at Texas A&M University and the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy, for providing computing resources useful in conducting the research reported in this work. The figures in this article have been created using the LevelScheme scientific figure preparation system.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)EDCBEE
Department of Energy (DOE)DEAC02-05CH11231
Department of Energy (DOE)DEFG02-07ER46433
Issue or Number:9
Record Number:CaltechAUTHORS:20160222-101712009
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160222-101712009
Official Citation:Calculation of dopant solubilities and phase diagrams of X–Pb–Se (X = Br, Na) limited to defects with localized charge Saurabh Bajaj, Heng Wang, Jeff W. Doak, Chris Wolverton and G. Jeffrey Snyder J. Mater. Chem. C, 2016, 4, 1769-1775 DOI: 10.1039/C5TC03970C
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64630
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:23 Feb 2016 00:49
Last Modified:03 Oct 2019 09:39

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