Abstract: The invention relates to the synthesis of silicon-containing nanoparticles by laser pyrolysis. For this purpose: a precursor (SiH4) containing the element silicon is conveyed, by a transport fluid (He), into a pyrolysis reactor (REAC); laser radiation (LAS) is applied, in the reactor, to a mixture that the transport fluid and the precursor form; and silicon-containing nanoparticles (nP) are recovered at the exit of the reactor. In particular, the power of the laser radiation is controlled. Furthermore, the effective pulse duration is controlled within a laser firing period. Typically, for a power greater than 500 watts and a pulse duration greater than 40% of a laser firing period, nanoparticles having a crystalline structure with a size of less than or of the order of one nanometre are obtained at a rate greater than or of the order of 80 milligrams per hour. Under optimum conditions, a record rate of greater than 740 milligrams per hour was able to be obtained.

Abstract: A process produces a crystal of a material with non-congruent melting using at least one first element and a second element. The process includes (a) placing, in a vertical alignment and maintaining under a controlled atmosphere, a bar of the first element gripped between a lower bar and an upper bar made out of the material, (b) transforming the bar of the first element into a floating zone by heating to a temperature that avoids the evaporation of the first element, the heating being obtained by heating means that provides a temperature gradient in the floating zone so that the lower face of the upper bar appears as a cold face, and (c) contra-rotating the lower and upper bars around the alignment axis and moving the whole bar assembly upwards in relation to the heating means in order to obtain the crystal on the cold face by growth in solution.