Low-Temperature Photochemically Activated Amorphous Indium-Gallium-Zinc Oxide for Highly Stable Room-Temperature Gas Sensors.

We report on highly stable amorphous indium-gallium-zinc oxide (IGZO) gas sensors for ultraviolet (UV)-activated room-temperature detection of volatile organic compounds (VOCs). The IGZO sensors fabricated by a low-temperature photochemical activation process and exhibiting two orders higher photocurrent compared to conventional zinc oxide sensors, allowed high gas sensitivity against various VOCs even at room temperature. From a systematic analysis, it was found that by increasing the UV intensity, the gas sensitivity, response time, and recovery behavior of an IGZO sensor were strongly enhanced. In particular, under an UV intensity of 30 mW cm(-2), the IGZO sensor exhibited gas sensitivity, response time and recovery time of 37%, 37 and 53 s, respectively, against 750 ppm concentration of acetone gas. Moreover, the IGZO gas sensor had an excellent long-term stability showing around 6% variation in gas sensitivity over 70 days. These results strongly support a conclusion that a low-temperature solution-processed amorphous IGZO film can serve as a good candidate for room-temperature VOCs sensors for emerging wearable electronics.

[1]  Chang-Hung Li,et al.  Room-temperature-operated sensitive hybrid gas sensor based on amorphous indium gallium zinc oxide thin-film transistors , 2011 .

[2]  Wenjun Yan,et al.  Hydrothermal synthesis porous silicon/tungsten oxide nanorods composites and their gas-sensing properties to NO2 at room temperature , 2015 .

[3]  Ming-Hung Chen,et al.  Novel Pt/TiO2–WO3 materials irradiated by visible light used in a photoreductive ozone sensor , 2014 .

[4]  G. Yang,et al.  Light-controlling, flexible and transparent ethanol gas sensor based on ZnO nanoparticles for wearable devices , 2015, Scientific Reports.

[5]  C. Ghanshyam,et al.  Detection mechanism of Metal Oxide Gas Sensor under UV Radiation. , 2004 .

[6]  Il-Doo Kim,et al.  Thin‐Wall Assembled SnO2 Fibers Functionalized by Catalytic Pt Nanoparticles and their Superior Exhaled‐Breath‐Sensing Properties for the Diagnosis of Diabetes , 2013 .

[7]  Richard J. Ewen,et al.  Highly sensitive room temperature sensors based on the UV-LED activation of zinc oxide nanoparticles , 2008 .

[8]  H. Ohta,et al.  Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors , 2004, Nature.

[9]  Donald A. Melnick.  Zinc Oxide Photoconduction, an Oxygen Adsorption Process , 1957 .

[10]  Yulin Deng,et al.  UV-Light-Activated ZnO Fibers for Organic Gas Sensing at Room Temperature , 2010 .

[11]  Chiu-Hsien Wu,et al.  Gas sensing properties of indium–gallium–zinc–oxide gas sensors in different light intensity , 2015 .

[12]  T. I. Barry,et al.  The reactions of oxygen at dark and irradiated zinc oxide surfaces , 1960, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[13]  Sunghoon Park,et al.  UV-enhanced NO2 gas sensing properties of SnO2-core/ZnO-shell nanowires at room temperature. , 2013, ACS applied materials & interfaces.

[14]  W. Y. Wang,et al.  Improvement in gas sensitivity of ZnO thick film to volatile organic compounds (VOCs) by adding TiO2 , 2004 .

[15]  Ren-Jang Wu,et al.  A dynamic equilibrium method for the SnO2-based ozone sensors using UV-LED continuous irradiation , 2014 .

[16]  Vinayak P. Dravid,et al.  UV-activated room-temperature gas sensing mechanism of polycrystalline ZnO , 2009 .

[17]  Shih-Chia Chang.  Oxygen chemisorption on tin oxide: Correlation between electrical conductivity and EPR measurements , 1980 .

[18]  S. Park,et al.  Light-induced hysteresis and recovery behaviors in photochemically activated solution-processed metal-oxide thin-film transistors , 2014 .

[19]  Yulin Deng,et al.  Enhancement of photoresponse and UV-assisted gas sensing with Au decorated ZnO nanofibers , 2012 .

[20]  Yanhong Lin,et al.  Photoelectric properties of ZnO/Ag2S heterostructure and its photoelectric ethanol sensing characteristics , 2012 .

[21]  Changsheng Xie,et al.  A comparative study on UV light activated porous TiO2 and ZnO film sensors for gas sensing at room temperature , 2012 .

[22]  Sun-Woo Choi,et al.  Room temperature CO sensing of selectively grown networked ZnO nanowires by Pd nanodot functionalization , 2012 .

[23]  Elisabetta Comini,et al.  UV light activation of tin oxide thin films for NO2 sensing at low temperatures , 2001 .

[24]  Jinhuai Liu,et al.  Porous flower-like SnO2 nanostructures as sensitive gas sensors for volatile organic compounds detection , 2012 .

[25]  Yong-Young Noh,et al.  Flexible metal-oxide devices made by room-temperature photochemical activation of sol–gel films , 2012, Nature.

[26]  Yeon-Tae Yu,et al.  The role of gold catalyst on the sensing behavior of ZnO nanorods for CO and NO2 gases , 2012 .

[27]  Noboru Yamazoe,et al.  Interactions of tin oxide surface with O2, H2O AND H2 , 1979 .

[28]  J. Rayappan,et al.  Electrospun tailored ZnO nanostructures – role of chloride ions , 2015 .

[29]  Xianzhi Fu,et al.  The correlation between the ethylene response and its oxidation over TiO2 under UV irradiation , 2012 .

[30]  Dermot Diamond,et al.  Advances in wearable chemical sensor design for monitoring biological fluids , 2015 .

[31]  Bo Li,et al.  A research on detection and identification of volatile organic compounds utilizing cataluminescence-based sensor array , 2013 .

[32]  Il-Doo Kim,et al.  Amorphous InGaZnO4 films: Gas sensor response and stability , 2012 .

[33]  Xiaogan Li,et al.  Room temperature impedance spectroscopy-based sensing of formaldehyde with porous TiO2 under UV illumination , 2013 .

[34]  Ho Won Jang,et al.  Self-Activated Transparent All-Graphene Gas Sensor with Endurance to Humidity and Mechanical Bending. , 2015, ACS nano.

[35]  A wearable and highly sensitive CO sensor with a macroscopic polyaniline nanofiber membrane , 2015 .

[36]  Sofian M. Kanan,et al.  Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection , 2009, Sensors.

[37]  I. Eisele,et al.  Light enhanced NO2 gas sensing with tin oxide at room temperature: conductance and work function measurements , 2003 .

[38]  N. Bârsan,et al.  Conduction Model of Metal Oxide Gas Sensors , 2001 .