H_(2) evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover.

Published

May 5, 2013

Author(s)

Daniel V. Esposito, Igor Levin, Thomas P. Moffat, Albert A. Talin

Abstract

Photoelectrochemical (PEC) water splitting represents a promising route for renewable production of hydrogen, but trade-offs between photoelectrode stability and efficiency have greatly limited the performance of PEC devices. In this work, we employ a metal–insulator–semiconductor (MIS) photoelectrode architecture that allows for stable and efficient water splitting using narrowbandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO_(2) layer and the use of bilayer metal catalysts. Scanning probe techniques were used to simultaneously map the photovoltaic and catalytic properties of the MIS surface and reveal the spillover-assisted evolution of hydrogen off the SiO_(2) surface and lateral photovoltage driven minority carrier transport over distances that can exceed 2 cm. The latter finding is explained by the photo- and electrolyte-induced formation of an inversion channel immediately beneath the SiO_(2)/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.

Citation

Nature Materials

Issue

3626

Pub Type

Journals

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Keywords

Hydrogen spillover, photoelectrochemicals cells, water splitting, MOS photoelectrodes, scanning electrochemical microscopy, laser beam induced current (LBIC)

Citation

Esposito, D. , Levin, I. , Moffat, T. and Talin, A. (2013), H_(2) evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover., Nature Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=912894 (Accessed March 14, 2025)