GROWTH AND CHARACTERIZATION OF Eu DOPED GaSe SINGLE CRYSTALS BY X-RAY DIFFRACTION AND RAMAN SPECTROSCOPY

Dumitru UNTILA*,**, Igor EVTODIEV*,**, Iuliana CARAMAN*** , Valeriu KANTSER*,** , Nicolae SPALATU****, Liliana DMITROGLO*, Silvia EVTODIEV* , Dorin SPOIALĂ* , Irina ROTARU*, Petru GAȘIN* *Moldova State University **Ghitu Institute of Electronic Engineering and Nanotechnologies, ASM ***Vasile Alecsandri University of Bacau (Romania) ****Tallinn University of Technology (Estonia)

Abstract

GaSe single crystals doped with Eu (0.025, 0.05, 0.5, 1.0 and 3.0 at%) were grown by Bridgman method using Ga, Se and Eu elementary components. The crystalline structure and vibration modes of the GaSe: Eu crystals lattice were studied by X-ray diffraction and Raman spectroscopy. Eu atoms arranged in the van der Waals space of GaSe: Eu crystals form Eu-Se valence bonds and restructure hexagonal lattice of GaSe leading to EuGa2Se4 crystallites formation. Defects generated by EuGa2Se4 crystallites lead to broadening and shifting of single phonon peaks present in Raman spectra towards shorter wavenumbers, and at the same time, activate the longitudinal optical vibrations of EuSe sublattice. Keywords: GaSe, doping, Eu, XRD, Raman.