MOLECULAR-DYNAMICS STUDY OF EPITAXIAL-GROWTH AND CLUSTER FORMATION ONMGO(001)

A new molecular dynamics (MD) code was developed to simulate the conti nuous deposition process of various molecules on substrates. In this m ethodology, various molecules can be deposited over substrate surfaces one by one in regular time intervals with definite velocity. It enabl es us to simulate home-and hetero-epitaxial growth process as well as cluster formation process on various substrates. This new MD code has been already applied to study the homoepitaxial growth and Au cluster formation processes on MgO(001). This article compares such phenomena as growth mode, temperature effect and influence of surface defects in . the homoepitaxial growth and Au cluster formation processes on the M gO(001), based on previous results. The continuous deposition process of MgO molecules was simulated. A 2-D smooth MgO layer without any def ects was formed at 1,000 K which was not realized at 300 K. High tempe rature is favorable for the complete layer-by-layer homoepitaxial grow th. The deposition process of Au atoms on the MgO(001) differed signif icantly from that of MgO molecules. A 3-D hemispherical Au cluster was constructed on the MgO(001) and low temperature was found to be desir ed for the fabrication of highly active supported Au-catalysts. The or igin of the different growth mode and the different temperature effect in the homo-epitaxial growth and Au cluster formation on the MgO(001) was clarified.