title: Synergistic Effects of a Combination of Cr2O3-Functionalization and UV-Irradiation Techniques on the Ethanol Gas Sensing Performance of ZnO Nanorod Gas Sensors.
abstract: There have been very few studies on the effects of combining two or more techniques on the sensing performance of nanostructured sensors. Cr2O3-functionalized ZnO nanorods were synthesized using carbothermal synthesis involving the thermal evaporation of a mixture of ZnO and graphite powders followed by a solvothermal process for Cr2O3-functionalization. The ethanol gas-sensing properties of multinetworked pristine and Cr2O3-functionalized ZnO nanorod sensors under UV illumination were examined to determine the effects of combining Cr2O3-ZnO heterostructure formation and UV irradiation on the gas-sensing properties of ZnO nanorods. The responses of the pristine and Cr2O3-functionalized ZnO nanorod sensors to 200 ppm of ethanol at room temperature by UV illumination at 2.2 mW/cm(2) were increased by 3.8 and 7.7 times, respectively. The Cr2O3-functionalized ZnO nanorod sensor also showed faster response/recovery and better selectivity than those of the pristine ZnO nanorod sensor at the same ethanol concentration. This result suggests that a combination heterostructure formation and UV irradiation had a synergistic effect on the gas-sensing properties of the sensor. The synergistic effect might be attributed to the catalytic activity of Cr2O3 for ethanol oxidation as well as to the increased change in conduction channel width accompanying adsorption and desorption of ethanol under UV illumination due to the presence of Cr2O3 nanoparticles in the Cr2O3-functionalized ZnO nanorod sensor.
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Park
authors.forename: Gun-Joo
authors.initials: GJ
authors.lastname: Sun
authors.affiliation: School of Mechanical Engineering, Konkuk University , Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Changhyun
authors.initials: C
authors.lastname: Jin
authors.affiliation: Department of Materials Science and Engineering, Hanyang University , Haengdang 1-dong, Seongdong-gu, Seoul 133-791, Republic of Korea.
authors.forename: Hyoun Woo
authors.initials: HW
authors.lastname: Kim
authors.forename: Sangmin
authors.initials: S
authors.lastname: Lee
authors.forename: Chongmu
authors.initials: C
authors.lastname: Lee
keywords: Cr2O3; UV; ZnO; nanorod; sensor