H2 evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover.

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 narrow bandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO2 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 SiO2 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 SiO2/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.

[1]  Adam Heller,et al.  Efficient p ‐ InP ( Rh ‐ H alloy ) and p ‐ InP ( Re ‐ H alloy ) Hydrogen Evolving Photocathodes , 1982 .

[2]  M. Pourbaix.  Atlas of Electrochemical Equilibria in Aqueous Solutions , 1974 .

[3]  Daniel J. Connelly,et al.  Fermi-level depinning for low-barrier Schottky source/drain transistors , 2006 .

[4]  Thomas F. Jaramillo,et al.  Addressing the terawatt challenge: scalability in the supply of chemical elements for renewable energy , 2012 .

[5]  P. Bertoncello.  Advances on scanning electrochemical microscopy (SECM) for energy , 2010 .

[6]  H. Lewerenz,et al.  Advances in photoelectrocatalysis with nanotopographical photoelectrodes. , 2010, Chemphyschem : a European journal of chemical physics and physical chemistry.

[7]  Jingguang G. Chen,et al.  A new photoelectrochemical test cell and its use for a combined two-electrode and three-electrode approach to cell testing. , 2009, The Review of scientific instruments.

[8]  G. Ghibaudo,et al.  Ultra-thin oxides grown on silicon (1 0 0) by rapid thermal oxidation for CMOS and advanced devices , 2001 .

[9]  T. Vo‐Dinh,et al.  Micro- and nanotopographies for photoelectrochemical energy conversion. II: Photoelectrocatalysis – Classical and advanced systems , 2011 .

[10]  Martin A. Green,et al.  Effects of pinholes, oxide traps, and surface states on MIS solar cells , 1978 .

[11]  J. Turner,et al.  Photoelectrochemistry with p‐Si electrodes: Effects of inversion , 1980 .

[12]  S. Morrison.  Electrochemistry at Semiconductor and Oxidized Metal Electrodes , 1980 .

[13]  M. Eikerling,et al.  Hydrogen Evolution at a Single Supported Nanoparticle: A Kinetic Model , 2003 .

[14]  R. Prins.  Hydrogen spillover. Facts and fiction. , 2012, Chemical reviews.

[15]  Yohan Park,et al.  Atomic layer-deposited tunnel oxide stabilizes silicon photoanodes for water oxidation. , 2011, Nature materials.

[16]  Yu-Lun Chueh,et al.  p-Type InP nanopillar photocathodes for efficient solar-driven hydrogen production. , 2012, Angewandte Chemie.

[17]  John L. Falconer,et al.  Spillover in Heterogeneous Catalysis , 1995 .

[18]  L. Su,et al.  Investigation of surface diffusion and recombination reaction kinetics of H-adatoms in the process of the hydrogen evolution reaction (her) at Au electrodes , 2004 .

[19]  Eric L. Miller,et al.  Photoelectrochemical production of hydrogen : Engineering loss analysis , 1997 .

[20]  Xiaobo Chen,et al.  Semiconductor-based photocatalytic hydrogen generation. , 2010, Chemical reviews.

[21]  A. Rinzler,et al.  Electrolyte-induced inversion layer Schottky junction solar cells. , 2011, Nano letters.

[22]  B. Kroposki,et al.  Renewable hydrogen production , 2008 .

[23]  T. Ohsaka,et al.  Hydrogen spillover phenomenon: Enhanced reversible hydrogen adsorption/desorption at Ta2O5-coated Pt electrode in acidic media , 2010 .

[24]  T. Vo‐Dinh,et al.  Photoelectrocatalysis: principles, nanoemitter applications and routes to bio-inspired systems , 2010 .

[25]  Carrie A. Farberow,et al.  Water-Mediated Proton Hopping on an Iron Oxide Surface , 2012, Science.

[26]  L. D. Kock.  Facts and fiction , 1996 .

[27]  K. Schulte,et al.  Combined photoelectrochemical conditioning and photoelectron spectroscopy analysis of InP photocathodes. I. The modification procedure , 2002 .

[28]  William H. Smyrl,et al.  A Novel Approach to Combine Scanning Electrochemical Microscopy and Scanning Photoelectrochemical Microscopy , 1995 .

[29]  R. Salzer,et al.  Investigations on hydrogen spillover. Part 1.—Electrical conductivity studies on titanium dioxide , 1995 .

[30]  Bruce E. Deal,et al.  Dependence of Interface State Density on Silicon Thermal Oxidation Process Variables , 1979 .

[31]  A. Bard,et al.  Screening of photocatalysts by scanning electrochemical microscopy. , 2008, Analytical chemistry.

[32]  M. Green,et al.  A 15% efficient silicon MIS solar cell , 1978 .

[33]  Stanley C. S. Lai,et al.  In situ scanning electrochemical probe microscopy for energy applications , 2012 .

[34]  Adam Heller,et al.  Hydrogen-Evolving Solar Cells , 1984, Science.

[35]  W. Kern.  Cleaning solutions based on hydrogen peroxide for use in silicon semiconductor technology , 1970 .

[36]  James R. McKone,et al.  Solar water splitting cells. , 2010, Chemical reviews.

[37]  W. Mönch.  On the alleviation of Fermi-level pinning by ultrathin insulator layers in Schottky contacts , 2012 .

[38]  U. Roland,et al.  On the nature of spilt-over hydrogen , 1997 .

[39]  Heather L. Tierney,et al.  Hydrogen dissociation and spillover on individual isolated palladium atoms. , 2009, Physical review letters.

[40]  Martin A. Green,et al.  Review of conductor-insulator-semiconductor (CIS) solar cells , 1981 .