title: Selective Oxidizing Gas Sensing and Dominant Sensing Mechanism of n-CaO-Decorated n-ZnO Nanorod Sensors.
abstract: In this work, we investigated the NO2and CO sensing properties of n-CaO-decorated n-ZnO nanorods and the dominant sensing mechanism in n-n heterostructured one-dimensional (1D) nanostructured multinetworked chemiresistive gas sensors utilizing the nanorods. The CaO-decorated n-ZnO nanorods showed stronger response to NO2than most other ZnO-based nanostructures, including the pristine ZnO nanorods. Many researchers have attributed the enhanced sensing performance of heterostructured sensors to the modulation of the conduction channel width or surface depletion layer width. However, the modulation of the conduction channel width is not the true cause of the enhanced sensing performance of n-n heterostructured 1D gas sensors, because the radial modulation of the conduction channel width is not intensified in these sensors. In this work, we demonstrate that the enhanced performance of the n-CaO-decorated n-ZnO nanorod sensor is mainly due to a combination of the enhanced modulation of the potential barrier height at the n-n heterojunctions, the larger surface-area-to-volume ratio and the increased surface defect density of the decorated ZnO nanorods, not the enhanced modulation of the conduction channel width.
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 Materials Science and Engineering, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Jae Kyung
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Seungbok
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
authors.forename: Wan In
authors.initials: WI
authors.lastname: Lee
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 133-791, Republic of Korea.
authors.forename: Hyoun Woo
authors.initials: HW
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.identifier: http://orcid.org/0000-0003-2750-8851
authors.initials: C
authors.lastname: Lee
keywords: CaO; NO2; ZnO; decoration; gas sensor