Rosenbluth, Mary L. and Lieber, Charles M. and Lewis, Nathan S. (1984) 630-mV open circuit voltage, 12% efficient n-Si liquid junction. Applied Physics Letters, 45 (4). pp. 423-425. ISSN 0003-6951 http://resolver.caltech.edu/CaltechAUTHORS:ROSapl84
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We report the first experimental observation of a semiconductor/liquid junction whose open circuit voltage Voc is controlled by bulk diffusion/recombination processes. Variation in temperature, minority-carrier diffusion length, and/or in majority-carrier concentration produces changes in the Voc of the n-Si/CH3OH interface in accord with bulk recombination/diffusion theory. Under AM2 irradiation conditions, the extrapolated intercept at 0 K of Voc vs T plots yields activation energies for the dominant recombination process of 1.1–1.2 eV, in accord with the 1.12-eV band gap of Si. A crucial factor in achieving optimum performance of the n-Si/CH3OH interface is assigned to photoelectrochemical oxide formation, which passivates surface recombination sites at the n-Si/CH3OH interface and minimizes deleterious effects of pinning of the Fermi level at the Si/CH3OH junction. Controlled Si oxide growth, combined with optimization of bulk crystal parameters in accord with diffusion theory, is found to yield improved photoelectrode output parameters, with 12.0±1.5% AM2 efficiencies and AM1 Voc values of 632–640 mV for 0.2-Ω cm Si materials.
|Additional Information:||© 1984 American Institute of Physics. Received 23 April 1984; accepted 21 May 1984. We acknowledge the National Science Foundation and the Research Corporation for support of this work. NSL also acknowledged support through and IBM Corp. Young Faculty Development Award. We thank Professor R. Swanson of Stanford for discussions concerning the high level injection regime, as well as for supply of the float zone Si samples. We also gratefully acknowledge the suggestion by Professor J. Gibbons of Stanford University and SERA Solar Corp. that residual series resistance losses might be important in improving the efficiency of the GaAs1-xPx/CH3CN system, because this suggestion prompted our investigation of the photoelectrochemsitry of the n-Si/liquid interface.|
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|Deposited By:||Tony Diaz|
|Deposited On:||13 May 2008|
|Last Modified:||26 Dec 2012 10:01|
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