<p>The silicon-gallium system’s nano-phase diagram, which takes into account the shape influence of the nanoparticles, has been evaluated for the first time using phase equilibrium and thermodynamic data. By using suitable thermodynamic models for the computation of the thermodynamic parameters, the impact of grain size has been taken into account. Ga nanoalloy has been studied in a variety of shapes, including icosahedral, spherical, hexahedral, octahedral, tetrahedral, film, and wire. The findings have been contrasted with data and empirical values from earlier research. It has been noted that thermodynamic characteristics such as the eutectic temperature, eutectic composition, and melting temperature of Si and Ga drop as particle size in the Ga–Si system decreases. The melting temperature of the nanoparticles is significantly influenced by the dimensions of the nanomaterials. The current work has made use of the dimension-based surface particle concentration, the total number of particles, and their relationship. Dimension of nanoparticles is important for analyzing their thermodynamic properties and phase diagram, in addition to their size.</p>