| The dynamics simulates of adsorption process of Sr O,Ba O and Ti O2 molecules on Ga N(0001) surfaces in 300 ℃, 400 ℃, 500 ℃, 600 ℃ and 700 ℃temperature are studied by Ab initio molecular dynamics methods based on first priciples.The energy of process and system,dynamic trajectory,the analysis of Mulliken population,ELF and diffusion coefficient are calculated and discussed.The results shows that the adsorption process of all small molecules have three stages including physical adsorption, chemical adsorption and stable adsorption. However temperature has different influence on the different adsorption system. The bonding atoms of O and Ga are different owing to different temperature. The bonding of O atom and Ga1 atom in Sr O is formed in 300℃,however O and Ga2 bonds in the other temperatures. The order of bonding of O atom and Ga atom in Ti O2 is different owing to temperature influence. The bonding of O1 and Ga2 atoms is earlier than O2 and Ga3 atoms in 300 ℃and 700℃, but the bonding of O2 and Ga3 atoms is earlier than O1 and Ga2 atoms in 400℃, 500 and 600℃ ℃. Temperature has influence on the rate of thin film growth. The higher the temperature is, the sooner the bonding time under normal circumstances. Temperature has influence on bond length of O-Ga. The higher the temperature is, the shorter the bond length. The temperature also has an effect on the final adsorption orientation. The temperature has the bigger effect on diffusion coefficient. Diffusion coefficient is small in low temperature, diffusion coefficient sharply increases in high temperature. But not the higher the temperature, the more stable adsorption. The optimal growth temperature of Sr O and Ba O is 600 and ℃Ti O2 is 500℃, which is highly consistent with the experiment optimal temperature of Ti O2 adsorption on Ga N(0001) surface. |
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