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|Author(s):||Daniel V. Esposito; Igor Levin; Thomas P. Moffat; Albert A. Talin;|
|Title:||H_(2) evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover.|
|Published:||May 05, 2013|
|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.|
|Pages:||pp. 1 - 7|
|Keywords:||Hydrogen spillover, photoelectrochemicals cells, water splitting, MOS photoelectrodes, scanning electrochemical microscopy, laser beam induced current (LBIC)|
|PDF version:||Click here to retrieve PDF version of paper (819KB)|