Room temperature CO gas sensing using Zn-doped In2O3 single nanowire field effect transistors

We demonstrate a room temperature sensing of CO gas (1-5 ppm) using high performance single Zn-doped In2O3 nanowire field effect transistors (Zn-In2O3 NW-FETs). Zn-In2O3 nanowires were grown in a horizontal CVD furnace, single Zn-In2O3 NW-FETs were fabricated using SiNx dielectric layer and bottom gate. Electrical measurements on the NW-FETs showed high performance devices, with a high ON current of 8 x 10(-6) A at a 5 V drain voltage, high on-off ratio of similar to 10(6) and electron mobility of 139 cm(2) V-1 s(-1) Sensing properties of CO gas were studied using these NW-FETs at room temperature Doping of Zn2+ into the In2O3 NW enhances the sensor response compared to pure In2O3 nanowire A good selectivity of CO gas over NO and NO2 can also be achieved The improved sensor response Si room temperature is attributed to the defects created and a change in conductivity of the nanowire upon Zn-doping Significant negative threshold voltage shift of -3.5 V was observed after exposure to a low concentration of CO gas at 5 ppm This approach represents an important step towards the room temperature sensing of hazardous gas (C) 2010 Elsevier B.V All rights reserved