2026-09-21T19:45:13Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/879562022-01-13T07:54:05Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Tonio Buonassisi.
Chakraborty, Rupak
Massachusetts Institute of Technology. Department of Mechanical Engineering.
Massachusetts Institute of Technology. Department of Mechanical Engineering
2014-06-13T22:36:16Z
2014-06-13T22:36:16Z
2014
2014
http://hdl.handle.net/1721.1/87956
880676056
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 67-70).
We investigate sub-bandgap absorption in pyrite FeS₂ single-crystals, using both natural and synthetic crystals. Both types of crystals show non-negligible magnitudes of sub-bandgap absorption. To test whether the origin of the residual sub-bandgap absorption is partially due to a lower bulk bandgap than previously thought, we conduct temperature-dependent electrical measurements on natural and synthetic crystals. Unlike previous measurements on pyrite, our electrical measurements are done in a sulfur atmosphere to avoid FeS formation. Using conductivity data in the intrinsic regime along with extrapolated Hall mobility data, the extracted bandgap is more than 0.1 eV lower than the literature value of 0.95 eV. However, higher-temperature Hall data are needed to gain a more reliable bandgap estimate.
by Rupak Chakraborty.
S.M.
70 pages
eng
Massachusetts Institute of Technology
M.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.
http://dspace.mit.edu/handle/1721.1/7582
Mechanical Engineering.
Investigation of sub-bandgap absorption in iron pyrite : optical and electrical measurements
Thesis
application/pdf
Publication
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<Abstract>We investigate sub-bandgap absorption in pyrite FeS₂ single-crystals, using both natural and synthetic crystals. Both types of crystals show non-negligible magnitudes of sub-bandgap absorption. To test whether the origin of the residual sub-bandgap absorption is partially due to a lower bulk bandgap than previously thought, we conduct temperature-dependent electrical measurements on natural and synthetic crystals. Unlike previous measurements on pyrite, our electrical measurements are done in a sulfur atmosphere to avoid FeS formation. Using conductivity data in the intrinsic regime along with extrapolated Hall mobility data, the extracted bandgap is more than 0.1 eV lower than the literature value of 0.95 eV. However, higher-temperature Hall data are needed to gain a more reliable bandgap estimate.</Abstract>
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