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Experimental Measurement of Quasi-Fermi Levels at an Illuminated Semiconductor/Liquid Contact

Tan, Ming X. and Kenyon, C. N. and Lewis, Nathan S. (1994) Experimental Measurement of Quasi-Fermi Levels at an Illuminated Semiconductor/Liquid Contact. Journal of Physical Chemistry, 98 (19). pp. 4959-4962. ISSN 0022-3654. doi:10.1021/j100070a002.

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A novel electrode geometry and contacting procedure has allowed measurement of the quasi-Fermi levels, i.e., the apparent electrochemical potentials, of electrons and holes at an illuminated semiconductor / liquid contact. The key feature of our experiments is the use of a lithographically patterned, high purity (100-400 Ω-km n-type float zone material), low dopant density Si sample in contact with CH_3OH-dimethylferrocene^(+/o) solutions. The photogenerated carriers can be collected at the back side of the Si sample through a series of diffused n+ and p^+ points. The lifetime of photogenerated carriers approaches 2 ms in this sample, indicating that electronhole recombination is minimized in the bulk of the semiconductor. Furthermore, surface recombination is minimized by use of low saturation current density, ohmic-selective contacts at the back of the sample. The solid/liquid contact also has a low recombination rate. Therefore, the potentials measured at the diffused points yield values for the quasi-Fermi levels of electrons and holes under illumination of the semiconductor/ liquid contact. Transient photovoltage measurements have also been performed to confirm quantitatively that the quasi-Fermi levels are flat across the Si samples used in this work.

Item Type:Article
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Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 1994 American Chemical Society. Received: September 7, 1993; In Final Form: March 12, 1994. We thank the National Science Foundation, Grant CHE-9221311, for support of this work. We also thank Drs. R. A. Sinton, R. M. Swanson, and P. J. Verlinden of SunPower Corp. for providing the lithographically patterned Si samples, and M.X.T. gratefully acknowledges the Link Foundation for a Graduate Fellowship.
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Link FoundationUNSPECIFIED
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Caltech Division of Chemistry and Chemical Engineering8858
Issue or Number:19
Record Number:CaltechAUTHORS:20180315-161240932
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Official Citation:Experimental Measurement of Quasi-Fermi Levels at an Illuminated Semiconductor/Liquid Contact. Ming X. Tan, C. N. Kenyon, and Nathan S. Lewis. The Journal of Physical Chemistry 1994 98 (19), 4959-4962 DOI: 10.1021/j100070a002
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85343
Deposited By: Tony Diaz
Deposited On:30 Mar 2018 22:22
Last Modified:15 Nov 2021 20:27

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