Molecular Dynamics Simulation Of Microstructure And Deposition Of Clusters Of Carbon Nitride

β-phase carbon nitride is a artificial covalence compound. Liu and Cohen indicated that its microstructure is similar withβ-phase silicon nitride and its hardness may exceed in diamond. To discuss physical mechanism of thin film growth and improve the thin film quality, it is crucial to study theβ-phase carbon nitride's microstructures and dynamics of carbon nitride thin films.Discover module in Materials Studio has been applied to study microstructures of crystal, liquid and amorphous phases of carbon nitride. The simulated results indicate that the coordination number of C in the structure of C3N4 is 3.92 and that of N is 3.07. The coordination polyhedron of C is tetrahedron. In the liquid state of C3N4, the coordination number of C and N is 3.61 and 2.52 respectively. The distribution of bond angle and bond length widens remarkably and the structure is disordered for liquid C3N4. The distribution of bond angle and bond length in amorphous phase C3N4 is similar to that in crystal C3N4. It indicates that the coordination polyhedron in crystal C3N4 is same as that in amorphous phase C3N4. The coordination number of C and N in amorphous phase C3N4 is 3.46 and 2.26 respectively, which is less than that in crystal structure.The deposition courses of C, N atom and C2, N2, CN clusters in WC(100) surface are simulated by molecular dynamics and the first-principles pseudopotential total energy methods. Physical and chemical adsorption model are builded to study the clusters (atoms) interactions with underlay surface in 298K, 500K, 700K. The interaction energy is calculated and clusters' adsorption mechanism in WC(100) surface is studied. To discuss the thin films growth in different underlay surface, the adsorption structure adsorption energy and bonding between atoms are also studyed in Si(100) and high-speed steel surface. The results show C and N atom can be attracted chemically by WC(100),Si(100) and HSS(110) surface, but C and N atom adsorbing on HSS(110) is stablest. N atom adsorbing on WC(100) surface is better than C atom. The WC(100) surface adsorbed by C2 cluster shows metal property. There is a intense ionic bond between W and CN when CN cluster adsorb on WC(110) surface. It is available to CN_x thin films growth on WC(110) substrate in 500K, on Si(110) substrate in 700K and on HSS(110) substrate in 298K.