We have investigated excimer laser irradiation of 2000-Å-thin as-deposited Al films on SiO 2 . Microstructural analysis of the irradiated films conducted with AFM and EBSD techniques reveals that there exists a wide energy density interval over which large equaxed grains with a strong (111) texture are obtained. Based on thermal, transformational, and microstructural considerations, we propose a heterogeneous nucleation model to account for the observed behaviors, and discuss the implication of the model on the phenomenon of heterogeneous nucleation of crystalline solids in condensed systems as regards the thermodynamic role played by the orientation of subcritical clusters.