A method of making an article of a semiconducting material involves selecting a target thickness for the article and then submerging a mold into a molten semiconducting material for a submersion time effective to form a solid layer of semiconducting material over an external surface of the mold where the thickness of the solid layer is substantially equal to the target thickness. The submersion time is selected to be substantially equal to a transition time, which is determined from a plot of solid layer thickness versus submersion time for a mold having particular attributes, including mold composition, mold thickness and initial mold temperature. The transition time, and thus the submersion time, corresponds to a maximum in solid layer thickness in the solid layer thickness versus submersion time curve for the particular mold.