Structural Analysis By Rietveld Method And Its Correlation With Optical Propertis Of Nanocrystalline Zinc Oxide

Vikash Kumar1, Swati Kumari1, Pawan Kumar2, Manoranjan Kar2, Lawrence Kumar1* 

1Center for Nanotechnology, Central University of Jharkhand Ranchi, Ranchi 835205, India

2Department of Physics, Indian Institute of Technology Patna, Patna 800013, India

Adv. Mater. Lett., 2015, 6 (2), pp 139-147

DOI: 10.5185/amlett.2015.5632

Publication Date (Web): Feb 08, 2015

E-mail: lawrencecuj@gmail.com

Abstract


The correlation between structural and optical properties of nanocrystalline ZnO synthesized by the citrate precursor method has been investigated. The Rietveld refinement of X-ray diffraction pattern confirms the P63mc space group and formation of single phase hexagonal wurtzite structure with presence of tensile strain at the lattice site. The presence of Raman active optical phonon mode at 436 cm-1 which is a significant character of ZnO with hexagonal wurtzite structure supports the XRD result. FE-SEM result shows that the size of the particle is about 20 nm with nearly spherical shapes. The optical band gap energy at room temperature has been calculated as 3.28 eV using the Tauc plot technique. The UV-Vis sub-gap absorption curve supports the presence of strain inside the crystal. The photoluminescence spectrum indicates the dominancy of the defect related deep level or trap state emissions over the near band edge UV emissions using an excitation wavelength of 320 nm.

Keywords

X-ray diffraction, rietveld, wurtzite, Raman spectroscopy, photoluminescence.

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