title: Fabrication and NO2 gas sensing performance of TeO2-core/CuO-shell heterostructure nanorod sensors.
abstract: TeO2-nanostructured sensors are seldom reported compared to other metal oxide semiconductor materials such as ZnO, In2O3, TiO2, Ga2O3, etc. TeO2/CuO core-shell nanorods were fabricated by thermal evaporation of Te powder followed by sputter deposition of CuO. Scanning electron microscopy and X-ray diffraction showed that each nanorod consisted of a single crystal TeO2 core and a polycrystalline CuO shell with a thickness of approximately 7 nm. The TeO2/CuO core-shell one-dimensional (1D) nanostructures exhibited a bamboo leaf-like morphology. The core-shell nanorods were 100 to 300 nm in diameter and up to 30 μm in length. The multiple networked TeO2/CuO core-shell nanorod sensor showed responses of 142% to 425% to 0.5- to 10-ppm NO2 at 150°C. These responses were stronger than or comparable to those of many other metal oxide nanostructures, suggesting that TeO2 is also a promising sensor material. The responses of the core-shell nanorods were 1.2 to 2.1 times higher than those of pristine TeO2 nanorods over the same NO2 concentration range. The underlying mechanism for the enhanced NO2 sensing properties of the core-shell nanorod sensor can be explained by the potential barrier-controlled carrier transport mechanism.
  61.46. + w; 07.07.Df; 73.22.-f.
authors.affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Sunghoon
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Soohyun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Gun-Joo
authors.initials: GJ
authors.lastname: Sun
authors.affiliation: Department of Chemistry, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Wan
authors.initials: W
authors.lastname: In Lee
authors.affiliation: Department of Nanooptical Engineering, Korea Polytechnic University, 2121 Jeongwangdong, Shiheung-city, Gyeonggido 429-793, Republic of Korea.
authors.forename: Kyoung Kook
authors.initials: KK
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Chongmu
authors.initials: C
authors.lastname: Lee
keywords: CuO shells; Gas sensors; NO2; Response; TeO2 nanorods