Gold-nanoparticle-functionalized In₂O₃ nanowires as CO gas sensors with a significant enhancement in response.

We present the room-temperature sensing of gold nanoparticle (AuNP)-functionalized In(2)O(3) nanowire field-effect transistor (NW-FET) for low-concentration CO gas. AuNPs were functionalized onto In(2)O(3) nanowires via a self-assembled monolayer of p-aminophenyltrimethoxysilane (APhS-SAM). The nanowires were mounted onto the Au electrodes with both ends in Schottky contacts. High sensor response toward low concentration of CO gas (200 ppb-5 ppm) at room temperature is achieved. The presence of AuNPs on the surface of In(2)O(3) nanowire serves to enhance the CO oxidation due to a higher oxygen ion-chemisorption on the conductive AuNP surfaces. Detailed studies showed that the sensing capabilities were greatly enhanced in comparison to those of bare nanowires or low coverage of Au NP-decorated nanowires. When the sensor is exposed to CO, the CO molecules interact with the preadsorbed oxygen ions on the AuNP surface. The CO oxidation on the AuNPs leads to the transfer of electrons into the semiconducting In(2)O(3) nanowires and this is reflected as the change in conductance of the NW-FET sensor. This work provides a promising approach for fabricating nanowire devices with excellent sensing capabilities at room temperature.

[1]  Chongwu Zhou,et al.  Detection of NO2 down to ppb levels using individual and multiple In2O3 nanowire devices , 2004 .

[2]  G. Ozin,et al.  A metal atom model for the oxidation of carbon monoxide to carbon dioxide. The gold atom-carbon monoxide-dioxygen reaction and the gold atom-carbon dioxide reaction , 1977 .

[3]  V. Zhdanov.  nm-sized metal particles on a semiconductor surface, Schottky model, etc. , 2002 .

[4]  Zhen Ma,et al.  Development of novel supported gold catalysts: A materials perspective , 2011 .

[5]  Martin Moskovits,et al.  Detection of CO and O2 Using Tin Oxide Nanowire Sensors , 2003 .

[6]  H. Haick,et al.  Controlling semiconductor/metal junction barriers by incomplete, nonideal molecular monolayers. , 2006, Journal of the American Chemical Society.

[7]  Chaoyi Yan,et al.  Room temperature CO gas sensing using Zn-doped In2O3 single nanowire field effect transistors , 2010 .

[8]  C. Li,et al.  Doping dependent NH3 sensing of indium oxide nanowires , 2003 .

[9]  Ian H. Stevenson,et al.  Principles and mechanisms of gas sensing by GaN nanowires functionalized with gold nanoparticles , 2006 .

[10]  A. Corma,et al.  Oxygen activation on gold nanoparticles: separating the influence of particle size, particle shape and support interaction. , 2010, Dalton transactions.

[11]  Howard E. Katz,et al.  Naphthalenetetracarboxylic Diimide-Based n-Channel Transistor Semiconductors: Structural Variation and Thiol-Enhanced Gold Contacts , 2000 .

[12]  A. I. Kozlov,et al.  Active Oxygen Species and Mechanism for Low-Temperature CO Oxidation Reaction on a TiO2-Supported Au Catalyst Prepared from Au(PPh3)(NO3) and As-Precipitated Titanium Hydroxide , 1999 .

[13]  J. Grunwaldt,et al.  Gold/Titania Interfaces and Their Role in Carbon Monoxide Oxidation , 1999 .

[14]  Ali Alavi,et al.  Catalytic role of gold in gold-based catalysts: a density functional theory study on the CO oxidation on gold. , 2002, Journal of the American Chemical Society.

[15]  D. Vuillaume,et al.  Suppression of charge carrier tunneling through organic self-assembled monolayers. , 1996, Physical review letters.

[16]  Martin Muhler,et al.  CO Oxidation over Supported Gold Catalysts—“Inert” and “Active” Support Materials and Their Role for the Oxygen Supply during Reaction , 2001 .

[17]  Ulrich Simon,et al.  Metal and metal oxide nanoparticles in chemiresistors: does the nanoscale matter? , 2006, Small.

[18]  M. Haruta,et al.  Chemical vapor deposition of gold on Al2O3, SiO2, and TiO2 for the oxidation of CO and of H2 , 1998 .

[19]  S. K. Gupta,et al.  Room-temperature H2S gas sensing at ppb level by single crystal In2O3 whiskers , 2008 .

[20]  S. Yitzchaik,et al.  Variable density effect of self-assembled polarizable monolayers on the electronic properties of silicon. , 2008, Journal of the American Chemical Society.

[21]  Noboru Yamazoe,et al.  Effects of additives on semiconductor gas sensors , 1983 .

[22]  M. Rumyantseva,et al.  Role of surface hydroxyl groups in promoting room temperature CO sensing by Pd-modified nanocrystalline SnO2 , 2010 .

[23]  R. Richmond,et al.  A procedure for determining the concentration of Hydroxyl Groups on Silica Surfaces , 1972 .

[24]  B. de Boer,et al.  Tuning of Metal Work Functions with Self‐Assembled Monolayers , 2005 .

[25]  J. Grunwaldt,et al.  Preparation of Supported Gold Catalysts for Low-Temperature CO Oxidation via “Size-Controlled” Gold Colloids , 1999 .

[26]  Nidhi Gupta,et al.  Microcalorimetry, adsorption, and reaction studies of CO, O2, and CO + O2 over Au/Fe2O3, Fe2O3, and polycrystalline gold catalysts , 1999 .

[27]  Zhong-Lin Wang,et al.  Schottky‐Gated Probe‐Free ZnO Nanowire Biosensor , 2009, Advances in Materials.

[28]  T. Shimoda,et al.  Control of carrier density by self-assembled monolayers in organic field-effect transistors , 2004, Nature materials.

[29]  R. G. Freeman,et al.  Preparation and Characterization of Au Colloid Monolayers , 1995 .

[30]  Elisabetta Comini,et al.  Sensing properties of different classes of gases based on the nanowire-electrode junction barrier modulation. , 2011, Nanoscale.

[31]  J. Geus,et al.  Adsorption of Carbon Monoxide on Pd(111) and Palladium Model Catalysts , 1997 .

[32]  Dmitri O. Klenov,et al.  Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles. , 2005, Nano letters.

[33]  L. Kronik,et al.  Molecular Control over Semiconductor Surface Electronic Properties: Dicarboxylic Acids on CdTe, CdSe, GaAs, and InP , 1999 .

[34]  Yuan Zhang,et al.  Self-assemblies of Pd nanoparticles on the surfaces of single crystal ZnO nanowires for chemical sensors with enhanced performances , 2009 .

[35]  Tae Il Lee,et al.  Fabrication and Characterization of ZnO Single Nanowire-Based Hydrogen Sensor , 2010 .

[36]  Gary W. Hunter,et al.  Metal-oxide nanostructure and gas-sensing performance ☆ , 2009 .

[37]  Koji Moriya,et al.  Indium oxide-based gas sensor for selective detection of CO , 1996 .

[38]  M. Srinivasan,et al.  Self-assembled molecular films of aminosilanes and their immobilization capacities. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[39]  Andrey Bratov,et al.  Enzyme semiconductor sensor based on butyrylcholinesterase , 1991 .

[40]  Giorgio Sberveglieri,et al.  Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts , 2002 .

[41]  Udo Weimar,et al.  Influence on the gas sensor performances of the metal chemical states introduced by impregnation of calcinated SnO2 sol–gel nanocrystals , 2000 .

[42]  Dominique Vuillaume,et al.  1-octadecene monolayers on Si(111) hydrogen-terminated surfaces: Effect of substrate doping , 2004 .

[43]  J. Morante,et al.  Micromachined twin gas sensor for CO and O2 quantification based on catalytically modified nano-SnO2 , 2006 .

[44]  L. Lauhon,et al.  Ferromagnetic self-assembled quantum dots on semiconductor nanowires. , 2006, Nano letters.

[45]  J. Brédas,et al.  Toward control of the metal-organic interfacial electronic structure in molecular electronics: a first-principles study on self-assembled monolayers of pi-conjugated molecules on noble metals. , 2007, Nano letters.

[46]  Rakesh K. Joshi,et al.  Au Decorated Zinc Oxide Nanowires for CO Sensing , 2009 .

[47]  L. T. Zhuravlev.  Concentration of hydroxyl groups on the surface of amorphous silicas , 1987 .

[48]  Zhiyong Fan,et al.  Gate-refreshable nanowire chemical sensors , 2005 .

[49]  J. Nørskov,et al.  Making gold less noble , 2000 .

[50]  D. Kohl.  The role of noble metals in the chemistry of solid-state gas sensors , 1990 .

[51]  M. Reed,et al.  Electron tunnelling in self-assembled monolayers , 2005 .

[52]  H. Haick,et al.  Electrostatic Properties of Ideal and Non‐ideal Polar Organic Monolayers: Implications for Electronic Devices , 2007 .

[53]  Zhong Lin Wang,et al.  Gigantic enhancement in sensitivity using Schottky contacted nanowire nanosensor. , 2009, Journal of the American Chemical Society.

[54]  Y. D. Kim,et al.  Size selectivity for CO-oxidation of Ag nanoparticles on highly ordered pyrolytic graphite (HOPG) , 2005 .

[55]  M. Bowker,et al.  Scanning tunnelling microscopy studies of the reactivity of the TiO2(110) surface: Re-oxidation and the thermal treatment of metal nanoparticles , 1999 .

[56]  D. Goodman,et al.  Structure sensitivity of CO oxidation over model Au/TiO22 catalysts , 1998 .