Above-bandgap voltages from ferroelectric photovoltaic devices

S. Y. Yang, J. Seidel, S. J. Byrnes, P. Shafer, C. H. Yang, M. D. Rossell, P. Yu, Ying-hao Chu, J. F. Scott, J. W. Ager, L. W. Martin, R. Ramesh

Research output: Contribution to journalArticlepeer-review

1037 Scopus citations

Abstract

In conventional solid-state photovoltaics, electron-hole pairs are created by light absorption in a semiconductor and separated by the electric field spaning a micrometre-thick depletion region. The maximum voltage these devices can produce is equal to the semiconductor electronic bandgap. Here, we report the discovery of a fundamentally different mechanism for photovoltaic charge separation, which operates over a distance of 1-2nm and produces voltages that are significantly higher than the bandgap. The separation happens at previously unobserved nanoscale steps of the electrostatic potential that naturally occur at ferroelectric domain walls in the complex oxide BiFeO 3. Electric-field control over domain structure allows the photovoltaic effect to be reversed in polarity or turned off. This new degree of control, and the high voltages produced, may find application in optoelectronic devices.

Original languageEnglish
Pages (from-to)143-147
Number of pages5
JournalNature nanotechnology
Volume5
Issue number2
DOIs
StatePublished - 1 Jan 2010

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