Experimental determination of physical parameters and analysis of the Bridgman-Stockbarger solidification for the growth AgGaSe2 crystal in ampoule with conical shape

In order to perform a numerical simulation of AgGaX2 (X = S or Se) crystal growth, thermal capacity of these materials was measured at high temperatur e. Values obtained are 0.08 cal g(-1) K-1(81 +/- 10 J mol(-1) K-1) until 62 3 K for AgGaS2, and of 0.09 cal g(-1) K-1 (126 +/- 10 J mol(-1) K-1 ) until 673 K for AgGaSe2. Thermal diffusivity was also determined for AgGaSe2, at 373 K (k = 0.0044 +/- 0.0001 cm(2) s(-1)) and T = 473 K(k = 0.0032 +/- 0.0 001 cm(2) s(-1)). Using the results of these measurements, numerical simula tion of the crystal growth of these materials was performed. A Physical mod el was defined on the basis of the experimental growth configuration. A col located finite volume method is used. The coupling between the pressure and the velocity field is solved with a no iterative PISO algorithm. For all c alculations, CFD2000/Storm software package is used. Numerical results are in good agreement with the observations made on crystals obtained experimen tally. (C) 1999 Elsevier Science B.V. All rights reserved.