This study utilized density functional theory (DFT) in quantum chemistry to investigate the gas-phase parasitic reaction mechanism between diethylzinc (DEZn) and tert-butanol (t-BuOH) during the metal-organic chemical vapor deposition (MOCVD) growth process of ZnO thin films. By calculating the Gibbs free energy changes along various reaction pathways at different temperatures, a comprehensive thermodynamic evaluation of key intermediates (HOZnOBut, H(ZnO)2But, HZnOH), as well as the formation of dimers (Zn2O2H4, Zn2O4H4, Zn4O4H4), and trimers (Zn3O6H6) was performed. The main objective was to identify potential pathways and products that could lead to the formation of nanoparticles, which might impede ZnO thin film growth. Research has shown that under high-temperature deposition conditions (673.15 K