AFM induced self-assembling and self-healing mechanism of silicon oxide nanoparticle linear array domains templated on Moire superlattice patterns on HOPG

Silicon oxide nanocluster suspensions were drop-cast on highly oriented pyrolytic graphite (HOPG) and investigated using ultra-high vacuum non-contact atomic force microscopy (AFM). The assembly of silicon oxide nanoparticle arrays was observed during consecutive scanning of the surface using AFM. The patterns and alignments of the nanoparticle arrays were consistent with templating on a Moire pattern in the top layers of the HOPG substrate. By halting and restarting the scanning process it was shown that the formation of nanoparticle arrays was driven by the AFM scan itself. Vacancy defects identified within the nanoparticle arrays were found to fill over time with nanoparticles; it was demonstrated that diffusion was preferred along the symmetry lines. This 'self-healing' mechanism was also shown to be driven by the AFM scanning. The recovery of defects within the arrays, and other observations of array dynamics, implied that the nanoparticle arrays had liquid-like qualities.Kirklareli University Scientific Research Coordination Office [KLUBAP 115]; Royal SocietyRoyal Society of LondonEuropean Commission [RP16G0214]; COST actionEuropean Cooperation in Science and Technology (COST) [CM1101]Part of this research was funded by Kirklareli University Scientific Research Coordination Office, project number KLUBAP 115. We are thankful for their support. K.v.H. acknowledges the financial support of a Research Grant from the Royal Society (RP16G0214)during the early phase of the project. K.v.H. and M.J.M. are grateful for financial support from COST action CM1101