Abstract To facilitate the development of CuCl-based optical devices, this study investigated strategies for enhancing the crystalline quality of CuCl thin films, the fabrication of multilayer structures, and methods for improving their long-term durability. Samples were fabricated on CaF 2 (111) substrates using molecular beam epitaxy and vacuum deposition. Our primary finding is that the combination of a CaF 2 homo-buffer layer and pre-deposition electron beam irradiation significantly enhances the crystalline quality. This was confirmed by AFM observations of oriented triangular structures and reflectance spectra yielding exciton coherence lengths that exceed the film thickness, signifying the achievement of high-quality growth. Additionally, the introduction of a Si capping layer maintained the film’s optical integrity for up to 384 hours, outperforming capping in long-term stability. These results, including the observations of pseudo-continuous structures in multilayered samples, provide essential guidance for the structural and material optimizations required to achieve stable, high-performance CuCl-based excitonic devices.