We study the interface energetics of Ag nanocrystals on a H-passivated Si(111) surface by a transmission electron microscopy experiment and molecular dynamics simulations. The annealed nanocrystals are oriented with $\mathrm{A}\mathrm{g}(111)\Vert \mathrm{S}\mathrm{i}(111)$. Azimuthally, epitaxy is preferred for nanocrystals with an interface larger than a coincident-site-lattice (CSL) cell. The equilibrium orientation, or interface energy minimum, depends on the interface size and shape. For interfaces approaching a CSL cell in size ($\sim 2\mathrm{n}\mathrm{m}$ nanocrystals), fluctuations of a single atom at an interface can lead to large variations in nanocrystal orientations.

• Received 9 October 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.226104