Extraordinary Improvement of Gas-Sensing Performances in SnO2 Nanofibers Due to Creation of Local p-n Heterojunctions by Loading Reduced Graphene Oxide Nanosheets

Title
Extraordinary Improvement of Gas-Sensing Performances in SnO2 Nanofibers Due to Creation of Local p-n Heterojunctions by Loading Reduced Graphene Oxide Nanosheets
Author
김현우
Keywords
sensing mechanism; SnO2 nanofibers; reduced graphene oxide; electronic sensitization
Issue Date
2015-01
Publisher
AMER CHEMICAL SOC
Citation
ACS APPLIED MATERIALS and INTERFACES, v. 7 Issue 5, Page 3101-3109
Abstract
We propose a novel approach to improve the gas-sensing properties of n-type nanofibers (NFs) that involves creation of local pn heterojunctions with p-type reduced graphene oxide (RGO) nanosheets (NSs). This work investigates the sensing behaviors of n-SnO2 NFs loaded with p-RGO NSs as a model system. n-SnO2 NFs demonstrated greatly improved gas-sensing performances when loaded with an optimized amount of p-RGO NSs. Loading an optimized amount of RGOs resulted in a 20-fold higher sensor response than that of pristine SnO2 NFs. The sensing mechanism of monolithic SnO2 NFs is based on the joint effects of modulation of the potential barrier at nanograin boundaries and radial modulation of the electron-depletion layer. In addition to the sensing mechanisms described above, enhanced sensing was obtained for p-RGO NS-loaded SnO2 NFs due to creation of local p-n heterojunctions, which not only provided a potential barrier, but also functioned as a local electron absorption reservoir. These mechanisms markedly increased the resistance of SnO2 NFs, and were the origin of intensified resistance modulation during interaction of analyte gases with preadsorbed oxygen species or with the surfaces and grain boundaries of NFs. The approach used in this work can be used to fabricate sensitive gas sensors based on n-type NFs.
URI
http://hdl.handle.net/20.500.11754/21228http://pubs.acs.org/doi/abs/10.1021/am5071656
ISSN
1944-8244
DOI
10.1021/am5071656
Appears in Collections:
COLLEGE OF ENGINEERING[S](공과대학) > MATERIALS SCIENCE AND ENGINEERING(신소재공학부) > Articles
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