Raman spectroscopy of WO 3 nano‐wires and thermo‐chromism study of VO 2 belts produced by ultrasonic spray and laser pyrolysis techniques

Novel optical and electrical properties of newly synthesized nano‐wires of monoclinic WO 3 and nano‐belts of rutile VO 2 have been investigated by Raman spectroscopy and thermo‐chromism studies respectively. Phonon confinement is observed in the WO 3 nano‐wires and the previously modified Richter equation is fitted to the experimental Raman spectroscopy data to obtain the optical phonon dispersion relations for the 713 cm –1 branch and the 808 cm –1 branch of WO 3 phonon spectra for the first time. Electrical measurements on the VO 2 nano‐belts at varying temperature reveal an enhanced hysteresis width of about 83 °C surpassing previously reported values on the thermo‐chromism studies on VO 2 . (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)