Eur. Phys. J. Appl. Phys. 37, 105–109 (2007) DOI: 10.1051/epjap:2007005 T HE EUROPEAN P HYSICAL JOURNAL APPLIED PHYSICS Enhancement of pyrolysis spray disposal performance using thermal time-response to precursor uniform deposition K. Boubaker 1, a , b , A. Chaouachi 1 , M. Amlouk 2 , and H. Bouzouita 1 1 Laboratoire de Photovolta¨ ıque et Mat´ eriaux Semi-conducteurs, L.P.M.S, ´ Ecole Nationale d’Ing´ enieurs, BP 37, Le Belv´ ed` ere, 1002 Tunis, Tunisia 2 Laboratoirede Physique de la Mati` ere Condens´ ee, Facult´ e des Sciences de Tunis, 2092 Tunis, Tunisia Received: 9 May 2006 / Accepted: 12 October 2006 Published online: 26 January 2007 – c  EDP Sciences Abstract. This paper proposes concrete enhancement of pyrolysis spray disposal performance. Solution to heat equation in particular cases of uniform and non-uniform fluid deposit is yielded as a guide to geomet- rical and temporal parameters control. Implemented models take into account simultaneously deposited material and targeted device thermal and geometrical properties. Theoretical temperature time-response features are compared to experiment in order to enhance deposition and solidification processes. PACS. 02.30.Cj Measure and integration – 07.05.Tp Computer modeling and simulation – 07.20.Pe Heat engines; heat pumps; heat pipes – 44.90.+c Other topics in heat transfer (restricted to new topics in section 44) 1 Introduction Spray pyrolysis technique (SPT) has been, during last twenty years one of major techniques to deposit a wide variety of materials on thin substrates. As long as main way to obtain good deposit quality is the optimization of preparative conditions (substrate temperature, spray rate, solution concentration); tremendous efforts were yielded in order to test new techniques [1–4] as ultrasonic nebu- lization, improved spray hydrolysis, corona spray pyrolysis and electrostatic spray pyrolysis. This technique (SPT) has been used as a method to prepare sub-micrometer layers and it is very suitable for the formation of high-density particles. In practice, the droplets of the solution generated by spray emitter can be transported with carrier gases down to a heated tar- get, where several reactions, such as solvent evaporation and atomic rearrangement take place successively. The ad- vantages of spray pyrolysis technique, in early used ver- sions are that the apparatus is simple and inexpensive, and that the final product composition can be easily con- trolled. Recently, various interesting materials, such as SnO 2 , CuInS 2 In 2 S 3 , Sn 2 S 3 and CuAlO 2 have been formed by this method [5]. In this study, we tried to perform theoretical models as a support to technique performance enhancement. Many recent works inside our team [1,3,6] noticed and empha- sized possibility of such enhancement, to which we try to a e-mail: boubaker karem@yahoo.com b Tutor of Doctoral candidate A. Chaouachi. give supply upon thermal and geometrical characteriza- tion of technical setup. 2 Spray pyrolysis technique In spray pyrolysis technique, a precursor solution is at- omized to an aerosol, which is directed to a heated sub- strate where a thin film is formed. This thin film depo- sition method is simple, practical and convenient as long as a wide choice of precursors can be used. The composi- tion of the film can be directly controlled by the precursor solution. Both, porous and dense structures can be deposited by this method [7,8] even on large substrates when scaling up the equipment. Different types of atomizers like ultrasonic, electrostatic or air blast can also be used in spray pyrolysis equipment. 2.1 Spray pyrolysis disposal In our studied equipment (Fig. 1a), precursor solution is carried and pulverized by means of a neutral gas (ni- trogen). It is blasted concordantly with gravity down to targeted surface. Setup consists mainly of the following parts [1,6]: a spraying unit, a liquid feeding unit, and a temperature control one (Fig. 1b). Targeted glass layer is a 2.0 cm × 2.0 cm × 0.2 cm par- allelepiped sample fixed on wide heating bulk maintained Article published by EDP Sciences and available at http://www.edpsciences.org/epjap or http://dx.doi.org/10.1051/epjap:2007005