TY - JOUR

T1 - Thermophysical properties of lithium thiogallate that are important for optical applications

AU - Kurus, Alexey

AU - Yelisseyev, Alexander

AU - Lobanov, Sergei

AU - Plyusnin, Pavel

AU - Molokeev, Maxim

AU - Solovyev, Leonid

AU - Samoshkin, Dmitry

AU - Stankus, Sergei

AU - Melnikova, Svetlana

AU - Isaenko, Lyudmila

N1 - Funding Information: Crystal growth and investigation of physical properties were supported by Russian Science Foundation, Russia (#19-12-00085). Spectroscopic study was performed on a state assignment of the Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences Russia and Ministry of Science and Higher Education, Russia. Measurements of thermal conductivity were funded by RFBR and Novosibirsk region (grant #20-42-543006\20). Publisher Copyright: © The Royal Society of Chemistry 2021.

PY - 2021/12/8

Y1 - 2021/12/8

N2 - Lithium thiogallate LiGaS2is one of the most common nonlinear crystals for mid-IR due to its extreme beam strength and wide transparency range; however, its thermophysical properties have not yet been practically studied. Large crystals of high optical quality are grown. DTA revealed features at 1224 K below melting point (1304 K) that are associated with the oxygen containing compounds of the LiGaO2−xSxtype. The thermal conductivity of LiGaS2(about 10.05 W (m−1K−1)) and band gap value (3.93 eV at 300 K) are found to be the highest in the LiBC2family. Isotropic points in the dispersion characteristics for the refractive index are found and LiGaS2-based narrow-band optical filters, smoothly tunable with temperature changes, are demonstrated. Intense blue photoluminescence of anionic vacanciesVSis observed at room temperature after annealing LiGaS2in vacuum, whereas orange low-temperature emission is related to self-trapped excitons. When LiGaS2crystals are heated, spontaneous luminescence (pyroluminescence) takes place, or thermoluminescence after preliminary UV excitation; the parameters of traps of charge carriers are estimated. The obtained data confirm the high optical stability of this material and open up prospects for the creation of new optical devices based on LiGaS2

AB - Lithium thiogallate LiGaS2is one of the most common nonlinear crystals for mid-IR due to its extreme beam strength and wide transparency range; however, its thermophysical properties have not yet been practically studied. Large crystals of high optical quality are grown. DTA revealed features at 1224 K below melting point (1304 K) that are associated with the oxygen containing compounds of the LiGaO2−xSxtype. The thermal conductivity of LiGaS2(about 10.05 W (m−1K−1)) and band gap value (3.93 eV at 300 K) are found to be the highest in the LiBC2family. Isotropic points in the dispersion characteristics for the refractive index are found and LiGaS2-based narrow-band optical filters, smoothly tunable with temperature changes, are demonstrated. Intense blue photoluminescence of anionic vacanciesVSis observed at room temperature after annealing LiGaS2in vacuum, whereas orange low-temperature emission is related to self-trapped excitons. When LiGaS2crystals are heated, spontaneous luminescence (pyroluminescence) takes place, or thermoluminescence after preliminary UV excitation; the parameters of traps of charge carriers are estimated. The obtained data confirm the high optical stability of this material and open up prospects for the creation of new optical devices based on LiGaS2

UR - http://www.scopus.com/inward/record.url?scp=85121535174&partnerID=8YFLogxK

U2 - 10.1039/d1ra05698k

DO - 10.1039/d1ra05698k

M3 - Article

C2 - 35492447

AN - SCOPUS:85121535174

VL - 11

SP - 39177

EP - 39187

JO - RSC Advances

JF - RSC Advances

SN - 2046-2069

IS - 62

ER -