Preparation of mixed arsenic/antimony chalcogenide glasses and some optical and thermo-physical properties G.P. Kothiyal a, * , Rakesh Kumar a , Madhumita Goswami a , V.K. Shrikhande a , D. Bhattacharya b , M. Roy c a Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai 400 085, India b Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085, India c Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India Available online 13 March 2007 Abstract The preparation of mixed glasses of As 2 S 3Àx Se x (x = 0–3) and (1 À y) Æ As 2 S 3 y Æ Sb 2 S 3 (y = 0–1) has been carried out by an in situ pouring technique. X-ray diffraction (XRD) was used to confirm the glassy nature of the materials and monitor devitrification. Visi- ble-IR transmission, photoluminescence, refractive index and micro-Raman were measured as a function of composition. Microhardness (MH) and thermal expansion coefficient (TEC) were also measured. Raman peaks in As 2 S 3 and As 2 Se 3 were observed around 338 cm À1 and 230 cm À1 , respectively in this first composition series in which S was replaced by Se. When As was replaced by Sb, in the case of second composition series, the As 2 S 3 related Raman peak became broader and shifted to lower wave number, reflecting some structural change/devitrification. MH increased (1.31–1.50 GPa) with Se and Sb content while the TEC was found to decrease (2.5–1.4 · 10 À5 /K). The progressive increase in the content of either Se or Sb in As 2 S 3 is anticipated to modify bond lengths and bond angles. The combined effect of these structural modifications would change the local structure of the glass forming a more rigid glass network thereby increasing the hardness and decreasing TEC. Ó 2007 Elsevier B.V. All rights reserved. PACS: 42.70.Ce; 78.55.Qr; 65.60.+a Keywords: Glass formation; Glass transition; Infrared glasses; Chalcogenides; Optical spectroscopy; Indentation, microindentation; Luminescence 1. Introduction Arsenic/antimony chalcogenides are attractive materials as infrared windows/lenses/prisms, optical fibers [1–5] photoconductors, electronic switching devices [4,6], and acousto – optic devices for IR optical processing [5,7–9] because of their non hygroscopic nature, chemical stability, resistance to devitrification and high resistivity. In the crys- talline state, binary compounds of arsenic chalcogenides such as As 2 S 3 , and As 2 Se 3 , are isostructural and have a quite large glass forming range in ternary systems [6,10]. On the other hand Sb 2 S 3 , is relatively difficult to synthesize in glassy form because of having a Sb coordination number greater than 3 when linked to S [11]. A number of studies have been reported on arsenic/antimony chalcogenides in both glass and crystalline forms since the early fifties. How- ever, in recent years a variety of new ternary and quater- nary systems with improved preparation potential have been synthesized [5,11–14] keeping in view some specific applications. Bulk glasses of these materials have found applications in optical systems as lenses, prisms, windows etc. as they offer more isotropic properties and flexibility over a wide composition range and their fibres could be used for laser-assisted surgery [15]. Although the optical and electronic properties of stoichiometric glass composi- tions such as As 2 S 3 , As 2 Se 3 , As 2 Te 3 , Sb 2 S 3 , Sb 2 Se 3 , and some mixed compositions are available in literature, their 0022-3093/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2006.09.053 * Corresponding author. Tel.: +91 22 25595652; fax: +91 22 25505296. E-mail address: gpkoth@barc.gov.in (G.P. Kothiyal). www.elsevier.com/locate/jnoncrysol Journal of Non-Crystalline Solids 353 (2007) 1337–1340