BACKGROUND: One of the most widely researched metal oxide
semiconductors for versatile applications is ZnO. Especially the wide
bandgap of 3.37 eV and large excitation energy of 60 meV makes it an
efficient semiconductor for various optical, electrical and thermal
applications. The promising applications of ZnO include UV absorbers, photo
catalysis, solar cells, field effect transistors etc.
METHODS: Hierarchical Zinc Oxide (ZnO) and Erbium doped Zinc Oxide (Er:ZnO)
nanostructures were successfully synthesized by using facile citrate and
polyethylene glycol (PEG) assisted hydrothermal process. The as-prepared ZnO
and Er:ZnO samples were characterized by X-ray diffraction analysis (XRD),
field emission scanning electron microscopy (FE-SEM), Photoluminescence (PL)
spectroscopy and UV–visible spectroscopy. The effect of doping on the
formation of distinctive morphology was systematically established.
RESULTS: Gas sensing activities of the as-prepared samples were monitored by
testing reducing gases like Acetone, Ethanol, Ammonia, TEA, EDA,
Formaldehyde and DMSO. The sensitivity towards the test gases was observed
to be increased after Er doping. Both ZnO and Er:ZnO displayed the maximum
response towards Acetone followed by TEA.
CONCLUSION: Hierarchical ZnO and 3% Er doped ZnO were prepared by facile PEG
and citrate assisted hydrothermal method. The structure, morphology and
optical properties were studied using various characterization methods. All
the properties were observed to be enhanced after doping with erbium. The
gas sensing properties at an optimum temperature of 3000C was investigated.
The sensitivity towards the test gases increased after doping. Both ZnO and
Er:ZnO displayed the maximum response towards Acetone followed by TEA.