Li/Na-doped CuO nanowires and nanobelts: Enhanced electrical properties and gas detection at room temperature

Oxide semiconductors are promising for gas sensing, but low-concentration gas sensing at room temperature (RT) remains a challenge. In this work, novel Li- and Na-doped CuO single-crystalline nanowires (NWs) and nanobelts (NBs) are synthesized using a low-cost process via stress-assisted growth and...

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Bibliographic Details
Published in:Journal of alloys and compounds 2017-03, Vol.696, p.79-85
Main Authors: Wang, Ruey-Chi, Lin, Ssu-Ni, Liu, Jia-yu
Format: Article
Language:English
Subjects:
Band gap
Chemical compounds
Conductivity
Crystal structure
CuO
Detection
Electric charge
Electrical properties
Electrical resistivity
Ethanol
Gas sensors
Nanobelt
Nanostructure
Nanowire
Nanowires
Red shift
Room temperature
Selectivity
Semiconductors
Sensitivity enhancement
Sensor
Single crystals
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Summary:Oxide semiconductors are promising for gas sensing, but low-concentration gas sensing at room temperature (RT) remains a challenge. In this work, novel Li- and Na-doped CuO single-crystalline nanowires (NWs) and nanobelts (NBs) are synthesized using a low-cost process via stress-assisted growth and in-situ doping. The results show that the dopants induce a morphological transformation from NWs to NBs. Tauc's plots show an increasing redshift in the optical band gap with increasing Li or Na concentration, with a maximum shift of 0.075 eV from 1.2 eV for Li-doped CuO. The devices made of doped one-dimensional (1D) nanostructures (NSs) demonstrate enhanced conductivity and RT gas sensing sensitivity. Li-doped CuO NSs exhibit the greatest improvement in conductivity (104-fold), and enhanced gas sensitivity and selectivity to ethanol at a low concentration of 2 ppm at RT. A Mulliken charge-related mechanism is proposed to explain the excellent sensing performance. •Novel Li- and Na-doped CuO nanowires and nanobelts were synthesized.•Optical band gaps of CuO 1D nanostructures were systematically adjusted.•Electrical conductivities of CuO 1D nanostructures were significantly improved.•Low-concentration gas sensing at room-temperature were remarkably enhanced.•A Mulliken charge-related mechanism was proposed to explain the unusual sensing enhancement.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2016.11.214