Investigation of structural and optical properties in LiInS2 single crystal grown by Bridgman-Stockbarger method for mid IR laser application

• With dimension of 10 mm × 25 mm LiInSe2 crystal was grown by Bridgman technique.
• Homemade graphite was used as crucible.
• The crystal perfection is found to be 82 arc s by HRXRD.
• More than 45% transmittance is achieved in the region of mid IR.

LiInS2 polycrystalline material was prepared by using graphite crucible in synthesis furnace. LiInS2 single crystals were successfully grown by Bridgman-Stockbarger method. The grown crystal was subjected to various characterization studies. XRD and HRXRD confirmed crystal formation and crystal perfection respectively. From UV- Vis-NIR analysis, transmittance of 25–35% was obtained in the range 550–1100 nm and optical band gap was calculated as 2.04 eV. Mid-IR transmittance of LiInS2 was more than 45 percentage which would be useful for mid IR laser application. The prominent peaks of LiInS2 were observed in emission spectra in blue band region. The most intense Raman line observed had the frequency of 271 cm−1 at room temperature, corresponding to the Г1 (W1) mode. The measurements were performed along the direction of grown crystal and the line frequency was found to be almost constant within the experimental accuracy. Its insignificant variation along the ingot suggests its structural and compositional uniformities.

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