Structural characterization of metastable hcp–Ni thin films epitaxially grown on Au(100) single-crystal underlayers

Abstract

Ni ( 11 2 ¯ 0 ) epitaxial thin films with hcp structure were prepared on Au(100) single-crystal underlayers at 100 °C by ultra high vacuum molecular beam epitaxy. The detailed film structure is studied by in situ reflection high energy electron diffraction, x-ray diffraction, and transmission electron microscopy. The hcp–Ni film consists of two types of variants whose c-axes are rotated around the film normal by 90° each other. An atomically sharp boundary is recognized between the film and the underlayer, where misfit dislocations are introduced. Presence of such dislocations seems to relieve the strain caused by the lattice mismatch between the film and the underlayer.