Methanol, Ethanol, and Hydrogen Sensing using Metal-Oxide and Metal (TiO subscript 2-Pt) Composite Nanoclusters on GaN Nanowires: A New Route towards Tailoring the Selectivity of Nanowire-Nanocluster based Chemical Sensors.

Published

May 12, 2012

Author(s)

Geetha G. Aluri, Abhishek Motayed, Albert Davydov, Vladimir Oleshko, Kristine A. Bertness, Norman Sanford, Mulpuri V. Rao

Abstract

We demonstrate a new method for tailoring the selectivity of chemical sensors using nanowires decorated with multicomponent nanoclusters (metal and metal-oxide)-based hybrid sensors. In the present study we demonstrate the change of selectivity of titanium dioxide (TiO2) nanoclusters-coated gallium nitride (GaN) nanowire sensor devices on addition of platinum (Pt) nanoclusters. The hybrid sensor devices were developed by fabricating two-terminal devices using individual GaN NWs followed by the deposition of TiO2 nanoclusters (NCs) using sputtering technique. The sensor fabrication process employed standard micro-fabrication techniques. The Pt NC deposition was also done in a sputtering tool. In this study we present the sensing characteristics of GaN/(TiO2-Pt) nanowire-nanocluster (NWNC) hybrids and GaN/(Pt) NWNC hybrids, and compare their selectivity with previously reported GaN/TiO2 sensors. The GaN/TiO2 NWNC hybrids showed remarkable selectivity to benzene and related aromatic compounds. They showed no measureable response when tested with other chemicals with different functional groups, such as alcohols, ketones, amides, alkanes, esters, chloroalkanes, and nitro alkanes. Addition of Pt NCs to GaN/TiO2 sensors dramatically altered their sensing behavior, making them sensitive only to alcohols (methanol and ethanol in specific) and to hydrogen, and not to any other chemicals. All these hybrid sensors worked at room temperatures and are photomodulated, i.e., they worked only in presence of UV excitation). The GaN/(TiO2-Pt) hybrids were able to detect ethanol and methanol concentrations as low as 100 ppb in air in about 100 sec. The GaN/(TiO-Pt) NWNC sensors were able to detect hydrogen concentrations from 1 ppm to 1% in nitrogen in less than 60 s. The detection limits for hydrogen is not our sensor's limitation but the measurement system's limitation for hydrogen. NOT ENOUGH SPACE PLEASE REFERENCE ATTACHED PAPER

Citation

Nanotechnology

Volume

23

Pub Type

Journals

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DOI Link

Keywords

Nanowire-Nanocluster Hybrid Gas Sensors, Photocatalytic Gas Sensors, TiO2-Pt Nanoclusters, Gallium Nitride Nanowire Gas Sensors

Citation

Aluri, G. , Motayed, A. , Davydov, A. , Oleshko, V. , Bertness, K. , Sanford, N. and Rao, M. (2012), Methanol, Ethanol, and Hydrogen Sensing using Metal-Oxide and Metal (TiO subscript 2-Pt) Composite Nanoclusters on GaN Nanowires: A New Route towards Tailoring the Selectivity of Nanowire-Nanocluster based Chemical Sensors., Nanotechnology, [online], https://doi.org/10.1088/0957-4484/23/17/175501 (Accessed April 26, 2024)