An Improvement of the Capacitance-Voltage Method to Determine the Band Offsets in a-Si:H/c-Si Heterojunctions
Due to the strong inversion layer at the c-Si interface, there may be errors in the determination of the band offsets in a-Si:H/c-Si heterojunctions from the usual capacitance-voltage (C-V) method. Considering the charge effect in the strong inversion layer, the theoretical differential capacitance...
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Published in | IEEE transactions on electron devices Vol. 61; no. 2; pp. 394 - 399 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
New York
IEEE
01.02.2014
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subjects | |
Online Access | Get full text |
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Summary: | Due to the strong inversion layer at the c-Si interface, there may be errors in the determination of the band offsets in a-Si:H/c-Si heterojunctions from the usual capacitance-voltage (C-V) method. Considering the charge effect in the strong inversion layer, the theoretical differential capacitance in (n + ) a-Si:H/(p) c-Si heterojunctions at high frequency is developed. The calculated results of the capacitance show that, the errors depend on the minority carrier density at the c-Si interface, and increase with increasing conduction band offset in (n + ) a-Si:H/(p) c-Si heterojunction solar cells. The apparent diffusion potential V int accounts for the charge effect in the inversion layer. Particularly, a modification to the apparent diffusion potential is presented, and the simulation results show that the modified apparent diffusion potential V int almost agrees with the theoretical value for various conduction band offsets. Accordingly, the band offsets are determined more precisely from the improved C-V method. However, there is still a small difference between VD and V int as well as slight errors at the high values of AEC. The improved C-V method is based on the usual C-V method and the static coplanar conductance measurement to determine the band offsets. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0018-9383 1557-9646 |
DOI: | 10.1109/TED.2013.2295459 |