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ACS Appl Mater Interfaces. 2017 Mar 22;9(11):9975-9985. doi: 10.1021/acsami.6b15995. Epub 2017 Mar 8.

Selective Oxidizing Gas Sensing and Dominant Sensing Mechanism of n-CaO-Decorated n-ZnO Nanorod Sensors.

Author information

1
Department of Materials Science and Engineering, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
2
Department of Mechanical Engineering, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
3
Department of Chemistry, Inha University , 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
4
Division of Materials Science and Engineering, Hanyang University , Seoul 133-791, Republic of Korea.

Abstract

In this work, we investigated the NO2 and 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 NO2 than 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.

KEYWORDS:

CaO; NO2; ZnO; decoration; gas sensor

PMID:
28244727
DOI:
10.1021/acsami.6b15995

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