Semiconductor nanocomposites have shown unique opto-electronic and thermal properties that could challenge state-of-the-art materials in various fields. Unfortunately, the high cost, slow growth, and material inflexibility exhibited by molecular beam epitaxy, the commonly used nanocomposite growth technique, limit applications in which these materials can be used, especially when thick films are needed. Here, we propose a 2-step growth process, which uses inert gas condensation to synthesize nanoparticles and liquid phase epitaxy to incorporate them into a thin film. Through these experiments, we have added to the understanding of the Ga-Er-As ternary phase diagram at high temperatures, and found criteria required for the growth of these nanocomposites. In summary, the nanoparticles must exhibit thermal stability, as well as thermodynamic compatibility in the growth solution, at the growth temperature to be compatible with liquid phase epitaxy growth. We have found bulk phase diagrams to be insufficient for these purposes.