Initial Stage of Ni Growth on the Mo(110) Surface

Abstract

Surface structures of Ni adsorbed on the Mo(110) surface have been studied using reflection high energy electron diffraction (RHEED). The surface phase diagram of Ni on the Mo(110) surface for annealing temperature vs Ni coverage has been completed. Both a two-dimensional layer and three-dimensional islands were observed in a thickness region of more than 1 ML (1 ML = 2.0 Å) and at annealing temperatures between 650°C and 850°C showing the Nishiyama-Wassermann orientation relationship on the Mo(110) substrate. The structure of the two-dimensional layer has a unit mesh of the distorted Ni(111) plane which is expanded by 0.9% in the [011]Ni direction and by 3% in the [112]Ni direction. The three-dimensional islands observed in the coverage of less than 15 ML have an atomic arrangement with a nearly six-fold symmetric structure of the distorted Ni(111) layer which is expanded uniformly by 3%. Both the layer and islands are commensurate with the Mo(110) lattice to form long-range-ordered structures.

Surface structures of Sn on Mo(110) surface investigated by RHEED

“…As shown in Fig. 2(b), 1 4 -ordered streaks between 00 and 21 reflection streaks of Mo and one Laue Zone of Sn between L 0 and L 1 appeared.…”

“…2(e). No reflection from Sn was observed between L 0 and L 1 ; and 1 3 -ordered streaks shown in Fig. 2(a) changed to 1 4 -ordered ones in Fig.…”

“…2(a) shows a RHEED pattern for the a structure with the incidence azimuth of [0 01]Mo which was observed when 0.5 ML of Sn was deposited and cooled down to R.T. The 1 3 -ordered streaks between 00 and 01 reflection streaks of Mo appeared, in which the intensity of streak indicated by ''a'' is stronger than the other two streaks. The streaks of ''a'' are main reflections from the a structure and other streaks are from multiple scattering.…”

“…In addition, two-dimensional surface structures at the deposition thickness near 1 ML has a specific structure deformed slightly from fcc(1 1 1) layer with N-W or K-S orientation relationship on bcc(1 1 0) substrate. According to the experiments of Reflection high-energy electron diffraction (RHEED), N-W orientation takes place in the first monolayer and crystallites of Ni [1], Pb [2], Ce [3], Nd [4] on Mo(1 1 0) surface and K-S one takes place in Ag [5], Au, Pd [6], Pt on Mo(1 1 0) surface. Interfacial energy calculation using Morse potential is tried to carry out to interpret the surface structures of the fcc deposited on bcc substrate [7].…”

Structure analysis of 1×1 Cu layer formed on Mo(110) surface

“…By increasing the film thickness to more than 1 monolayer, the fcc metal forms (1 1 1) or nearly (1 1 1) monolayer on the bcc (1 1 0) surface with certain crystallographic orientations. The epitaxial orientations, despite the geometrical asymmetry, exist in the combination of the densely packed fcc (1 1 1) and bcc (1 1 0) planes; the so-called Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W) orientation relationships have been experimentally observed in these interfaces, such as Ag, Au, Pd, and Pt on 11.191 Mo(1 1 0) [1][2][3] with K-S orientation and Ni, Pb, Ce, and Nd on Mo(1 1 0) [4][5][6][7] with N-W orientation. Interfacial energy calculations for elucidating the origin of the epitaxial orientation have also been performed on the fcc/bcc system [8,9].…”