Gangwar, Jitendra and Gupta, Bipin Kumar and Kumar, Pawan and Tripathi, Surya Kant and Srivastava, Avanish Kumar
(2014)
Time-resolved and photoluminescence spectroscopy of theta-Al2O3 nanowires for promising fast optical sensor applications.
Dalton Transactions, 43 (45).
17034-17043.
ISSN 1477-9226
Abstract
Herein, we have demonstrated the high yield facile growth of Al2O3 nanowires of uniform morphology with different polymorph phases (e.g. gamma, delta and theta) via a hydrothermal method with varying calcination temperatures. The synthesized theta-Al2O3 nanowires were well characterized by XRD, FTIR, SEM/EDAX, AFM and HRTEM techniques. Microstructural analysis confirmed that the dimensions of the individual theta-Al2O3 nanowires are approximately in the ranges 5-20 nm in width and 40-150 nm in length, and the aspect ratio is up to 20. AFM results evidenced the uniform distribution of the nanowires with controlled morphology. Furthermore, UV-vis spectroscopic data reveal that the estimated optical band gap of the theta-Al2O3 nanowires was similar to 5.16 eV. The photoluminescence spectrum exhibits blue emission upon excitation at a wavelength of 252 nm. Time-resolved spectroscopy demonstrates that these nanowires illustrate a decay time of similar to 2.23 nanoseconds. The obtained photoluminescence results with a decay time of nanoseconds suggest that the theta-Al2O3 phase could be an exceptional choice for next generation fast optical sensors.
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