Investigation of optical properties and local structure of Gd3+ doped nano-crystalline GeSe2

Abstract

Pure and Gd-doped nano-crystalline GeSe2 were prepared by the melt-quenching technique. Structure analysis using Rietveld program suggests monoclinic structure for both virgin and doped samples with nano-particle size 41 nm for GeSe2 and 48 nm for Gd-doped sample. A wide optical band gap as estimated from absorbance measurements is 4.1 and 4.8 eV for pure and doped samples in accordance with the confinement effects. Raman spectra show two unresolved components at [Formula: see text]202 cm[Formula: see text] with broad line width. Also, well identified low intensity ([Formula: see text] [Formula: see text] 145 cm[Formula: see text]) and high intensity ([Formula: see text] [Formula: see text] 250 cm[Formula: see text]) bands are detected. For Gd-doped sample, the main band is shifted to lower energies and its full width at half maximum (FWHM) is reduced by [Formula: see text]50% accompanied by an intensity increase of about [Formula: see text]17 fold times. The photoluminescence analysis of the pure sample shows a main emission band at [Formula: see text]604 nm. This band is split into two separated bands with higher intensity. The detected emission bands at wavelength [Formula: see text]650 nm are assigned to transmission from 6G[Formula: see text] to the different 6P[Formula: see text] terms.