tailieunhanh - Báo cáo hóa học: " Morphology and Photoluminescence of HfO2 Obtained by Microwave-Hydrothermal"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Morphology and Photoluminescence of HfO2 Obtained by Microwave-Hydrothermal | Nanoscale Res Lett 2009 4 1371-1379 DOI S11671-009-9407-6 NANO EXPRESS Morphology and Photoluminescence of HfO2 Obtained by Microwave-Hydrothermal S. A. Eliziario L. S. Cavalcante J. C. Sczancoski P. S. Pizani J. A. Varela J. W. M. Espinosa E. Longo Received 26 June 2009 Accepted 22 July 2009 Published online 13 August 2009 to the authors 2009 Abstract In this letter we report on the obtention of hafnium oxide HfO2 nanostructures by the microwavehydrothermal method. These nanostructures were analyzed by X-ray diffraction XRD field-emission gum scanning electron microscopy FEG-SEM transmission electron microscopy TEM energy dispersive X-ray spectrometry EDXS ultraviolet-visible UV-vis spectroscopy and photoluminescence PL measurements. XRD patterns confirmed that this material crystallizes in a monoclinic structure. FEG-SEM and TEM micrographs indicated that the rice-like morphologies were formed due to an increase in the effective collisions between the nanoparticles during the MH processing. The EDXS spectrum was used to verify the chemical compositional of this oxide. UV-vis spectrum revealed that this material have an indirect optical band gap. When excited with 488 nm wavelength at S. A. Eliziario J. A. Varela J. W. M. Espinosa E. Longo IQ-LIEC Universidade Estadual Paulista . Box 355 14801-907 Araraquara SP Brazil e-mail sayonara@ J. A. Varela e-mail varela@ J. W. M. Espinosa e-mail jose@ E. Longo e-mail elson@ L. S. Cavalcante J. C. Sczancoski El P. S. Pizani LIEC Departamento de Quimica e Fisica Universidade Federal de Sao Carlos . Box 676 13565-905 Sao Carlos SP Brazil e-mail jcsfisica@ L. S. Cavalcante e-mail laeciosc@ P. S. Pizani e-mail pizani@ room temperature the HfO2 nanostructures exhibited only one broad PL band with a maximum at around 548 nm green emission . Keywords HfO2 Nanoparticles Morphology Optical band gap Photoluminescence Introduction Currently the