article.page.titleprefix Growth and temperature-tuned band gap characteristics of LiGd(MoO4)2 single crystals for optoelectronic applications
Date
2023-08-01
Journal Title
Journal ISSN
Volume Title
Publisher
Ceramics International
Abstract
LiGd(MoO4)2 has been investigated due to its optoelectronic applications, especially for development of light-emitting diodes. In the present paper, LiGd(MoO4)2 single crystals grown by Czochralski method was studied in terms of structural and temperature dependent optical properties. X-ray diffraction analysis showed that the crystal crystallizes in a single phase tetragonal structure. Raman spectrum exhibited six distinguishable peaks around 207, 319, 397, 706, 756 and 890 cm−1. These peaks correspond to vibrational modes of free rotation, symmetrical stretching, symmetric bending, antisymmetric stretching and antisymmetric bending of (MoO4)2− tetrahedron. Infrared transmittance spectrum had six minima around 2114, 2350, 2451, 2854, 2929, 2960, 3545 and 3578 cm−1 which are due to multiphonon absorptions. Spectral change of transmittance curves at various temperature between 10 and 300 K was utilized to elucidate temperature effect on absorption characteristics. Optical band gap of the material was found using Tauc and spectral derivative methods. The band gap value was obtained as 3.09 eV at room temperature and this value increased to 3.22 eV with decreasing temperature down to 10 K. The detailed analysis on the temperature dependency of the band gap was applied by Varshni model and the band gap at 0 K and change of rate of the band gap were estimated as 3.23 eV and −1.45 × 10−3 eV/K, respectively. Room temperature photoluminescence spectrum of the crystal presented a peak around 709 nm which corresponds to red light emission. LiGd(MoO4)2 is a potential candidate for optoelectronic devices emitting red light.
Description
Published by Ceramics International, https://doi.org/10.1016/j.ceramint.2023.05.131, S. Delice, Department of Physics, Hitit University, 19040 Çorum, Turkey, M. Isik, Department of Electrical and Electronics Engineering, Atilim University, 06836 Ankara, Turkey, N.M. Gasanly, Department of Physics, Middle East Technical University, 06800, Ankara, Turkey, Virtual International Scientific Research Centre, Baku State University, 1148 Baku, Azerbaijan, N.H. Darvishov, V.E. Bagiev, Institute of Physical Problems, Baku State University, 1148 Baku, Azerbaijan.
Keywords
Scheelites, Double Molybdates, Optical properties, LEDs, Optoelectronic devices
Citation
http://hdl.handle.net/20.500.14411/1827