Field quenching in photoconductive CdS as possible reason to enhance Voc and FF in thin-film solar cells

Field‐quenching via Frenkel–Poole excitation of Coulomb attractive hole traps limits the field in the CdS part of the junctions to 50 kV/cm. This is far below the field in typical other pn‐junctions of thin‐film semiconductors, which exceeds 100 kV/cm and approaches tunneling fields that make juncti...

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Bibliographic Details
Published in:Physica status solidi. A, Applications and materials science Applications and materials science, 2009-11, Vol.206 (11), p.2665-2668
Main Author: Böer, Karl W.
Format: Article
Language:English
Subjects:
71.55.Gs
73.40.Lq
73.50.Gr
73.50.Gz
73.61.Ga
78.20.Jq
Applied sciences
Energy
Exact sciences and technology
Natural energy
Photovoltaic conversion
Solar cells. Photoelectrochemical cells
Solar energy
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Summary:Field‐quenching via Frenkel–Poole excitation of Coulomb attractive hole traps limits the field in the CdS part of the junctions to 50 kV/cm. This is far below the field in typical other pn‐junctions of thin‐film semiconductors, which exceeds 100 kV/cm and approaches tunneling fields that make junctions leaky, hence reduces both Voc and FF. Field‐quenched CdS may become electronically inverted, thereby providing a possibility that the junction of the CdS/CdTe cell may extend into the CdS, with the cell becoming a hetero structure. With field quenching a region of negative differential conductivity is created causing a high‐field domain that prevents the maximum electric field in the junction to exceed 50 kV/cm, avoiding tunneling, hence electron leakage through it. A preliminary band model of this cell is proposed.
ISSN:1862-6300
1862-6319
DOI:10.1002/pssa.200925291