Effect of in and Zn additives on some thermal properties of a-Se N. Mehta a, * , K. Singh a , N.S. Saxena b a Department of Physics, Banaras Hindu University, Varanasi, India b Semiconductor and Polymer Science Laboratory, 5-6, Vigyan Bhawan, Department of Physics, University of Rajasthan, Jaipur, India article info Article history: Received 1 September 2009 Received in revised form 5 January 2010 Accepted 13 January 2010 Available online 20 January 2010 Keywords: Thermal conductivity Thermal diffusivity Specific heat per unit volume Transient plane source (TPS) technique abstract In the present work, the effect of In and Zn on some thermo–physical properties (thermal conductivity, diffusivity and specific heat per unit volume) of amorphous Se (a-Se) have been studied. For this, simultaneous measurements of effective thermal conductivity (l e ) and effective thermal diffusivity (c e ) are used at room temperature for twin pellets of Se, Se 90 In 10 and Se 90 Zn 10 alloys using transient plane source (TPS) technique. It has been found that In and Zn additives changes significantly the values of thermo-physical properties (thermal conductivity, diffusivity and specific heat per unit volume) of a-Se studied in the present work. The results have been analyzed in terms of average bond strength and effective molecular weight of the binary alloys. Ó 2010 Elsevier Masson SAS. All rights reserved. 1. Introduction Studies of the chalcogenide materials as photographic materials have received great attention because of their important applica- tions in the fields of lasers and fiber techniques [1–3]. Recently, Se based alloys with In and Zn as chemical modifiers have found various attractive applications [4–9]. Zn–Se alloys with wide band gap are an example of potential applications in optoelectronic devices like blue light emitting diodes and blue diode lasers. These Zn–Se diode lasers work in blue–green region [4]. They can also be used in short-wavelength visible-light laser devices [5]. In addition, Zn–Se system is one of the most capable materials for use in white Light Emitting Diodes (LEDs) and infrared lenses [6]. The use of Zn–Se system for indus- trial applications needs that the alloys of this system should be synthesized economically. Recently, it is also pointed out that Se–In alloys have more advantages than amorphous Se (a-Se) due to their greater hardness, higher crystallization temperature, higher photosensitivity and smaller ageing effects. The energy band gap of glassy Se–In alloys is about 1.3 eV at 300 K [7]. This value is close to the theoretical optimum for solar energy conversion and hence several attempts have been made to utilize glassy Se–In alloys in solar cells [8,9]. Therefore, glassy Se–In alloys are used to extend the utility of a-Se. In order to make use of this material in industrial applications, a better understanding of their physical properties is desirable. The knowledge of thermo–physical properties of a material in bulk form is helpful from structural point of view. Studies on the thermo–physical properties like thermal conductivity, thermal diffusivity and specific heat per unit volume provide an insight about the various scattering processes that serve to limit the mean free path of heat carriers i.e., phonons in these materials. Thus it can be used as a method in the study of structural changes in the material with temperature [10]. In our previous paper, we have reported temperature depen- dence of effective thermal conductivity and diffusivity of Zn x Te 100x (x ¼ 5, 10, 30 and 50) chalcogenide material [11]. Recently we have reported the comparative analysis of some thermo–physical properties of Se 90 Zn 10 and Te 90 Zn 10 alloys [12]. In the present work, the effect of In and Zn additives on the thermo–physical properties of a-Se has been studied. Our results can provide some new explanations in this direction to under- stand the effect of structure on the thermo–physical properties of non-crystalline or disordered solids. 2. Material synthesis High purity (99.99%) Selenium granules with fine Zn and In dust are weighed in two separate quartz glass ampoule (length 5 cm and internal diameter 8 mm) in appropriate atomic percentage. The content of each ampoule is sealed in a vacuum of 10 6 Torr and heated in a furnace where temperature was raised at a rate of 3–4 K * Corresponding author. Tel.: þ91 542 2307308x244; fax: þ91 542 2368174. E-mail address: dr_neeraj_mehta@yahoo.co.in (N. Mehta). Contents lists available at ScienceDirect Solid State Sciences journal homepage: www.elsevier.com/locate/ssscie 1293-2558/$ – see front matter Ó 2010 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.solidstatesciences.2010.01.028 Solid State Sciences 12 (2010) 963–965