Investigations on synthesis, growth and physical characterization of lithium selenoindate single crystals P. Vijayakumar a , M. Magesh a , A. Arunkumar a , G. Anandha Babu a , P. Ramasamy a,n , K.G.M. Nair b a Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603110, Tamilnadu, India b Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamilnadu, India article info Keywords: A1. Characterization A1. Solidification A2. Bridgman technique B1. Lithium compounds B2. Semiconducting ternary compounds abstract Crack free LiInSe 2 single crystal with bottom dimension of 8 mm diameter and 10 mm length and top dimension of 12 mm diameter and 22 mm length was grown using modified vertical Bridgman–Stockbarger method with steady ampoule rotation. The grown LiInSe 2 crystal was characterized by X-ray diffraction pattern, Rutherford backscattering spectroscopy (RBS) analysis, Thermogravimetric-Differential thermal (TG-DTA) analysis, optical transmission and microhardness measurements. X-ray diffraction pattern gives the orientation of the crystal as 〈002〉. RBS analysis confirms that the composition of the grown crystal is Li 0.8 In 1.16 Se 2.04 . TG-DTA analysis confirms that the melting point of the grown crystal is 897.5 1C. Optical behavior has been assessed by ultraviolet–visible–near infrared spectroscopy and Fourier transform infrared analysis. LiInSe 2 optical band gap energy is 2.72 eV and the cut off wavelength is 450 nm. Mechanical behavior has been studied using Vickers Microhardness measurements. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Crystal materials which can work efficiently on the widely tunable coherent mid-infrared laser sources in the range of 3–20 μm, specially in the band of 3–5 μm and 8–14 μm of the three atmospheric transparent windows, a spectral range of impor- tance for infrared (IR) laser technology [1], remains a continuing challenge. Ternary chalcogenides with the general formula A I B III C VI 2 (A¼ Li, Na, Cu, Ag; B ¼ Al, Ga, In; C ¼ S, Se, Te) are of considerable interest because of their potential optoelectronic applications as light emitting diodes (LED), nonlinear optical (NLO) devices, detec- tors and solar energy converters [2]. The lithium-containing A I B III C VI 2 -type semiconductors are little known because of difficulties of crystal growth caused by the chemical activities of lithium and volatility of the chalcogens. However, lithium alkali metal ternary semiconductors are of interest because they have larger band gaps than the corresponding noble-metal compounds. There is a reason that makes the Li-based crystals very attractive for nonlinear optics, Ag-ion replaced by lighter Li-ion results in the increase in the frequencies in the crystal lattice vibrations and on Debye tempera- ture. It increases the thermal conductivity, which in turn, is accompanied by an increase in optical damage threshold. Particu- larly, LiInSe 2 has excellent properties, such as wide transparency range (0.45–13 mm), lower band gap (2.86 eV), high NLO coefficients (11.7 pm/V), nearly isotropic thermal expansion behavior and being phase matchable over a large wavelength range [3]. Most recently, nuclear radiation detection device was fabricated using the vertical Bridgman method grown LiInSe 2 single crystal [4]. Many authors [5–6] have investigated the conditions of growth of these crystals by directional solidification technique [7–9]. Many reports are available for synthesis, growth and character- ization of LiInSe 2 crystal, however there is no report available on the basic properties and compositional analysis. Smith et.al reported the composition of reddish LiInSe 2 crystal powder, however the composition gave a strange variation [10] and there is no other report available on the compositions of LiInSe 2 . The melt and temperature oscillation method (MTOM) results in homogeneous polycrystalline material [11–14]. Based on these, LiInSe 2 polycrystal- line material was synthesized and single crystal was grown using the modified vertical Bridgman–Stockbarger method with steady ampoule rotation. We have characterized the grown crystal for its composition. In this investigation, we discuss the synthesis, crystal growth and physical characterizations like X-Ray diffraction pattern (XRD), thermogravimetric-differential thermal (TG-DTA) analysis, Rutherford backscattering spectroscopy (RBS) analysis, ultraviolet– visible–near infrared (UV–vis–NIR), Fourier transform infrared (FTIR) spectroscopy and Vickers Microhardness measurements of LiInSe 2 single crystals. Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jcrysgro Journal of Crystal Growth 0022-0248/$ - see front matter & 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jcrysgro.2013.12.026 n Corresponding author. Tel.: þ91 9283105760, þ91 44 27475166. E-mail addresses: ramasamyp@ssn.edu.in, proframasamy@hotmail.com (P. Ramasamy). Please cite this article as: P. Vijayakumar, et al., Journal of Crystal Growth (2014), http://dx.doi.org/10.1016/j.jcrysgro.2013.12.026i Journal of Crystal Growth ∎ (∎∎∎∎) ∎∎∎–∎∎∎