RHEED STUDY OF PD PARTICLE GROWTH ON ALPHA-ALUMINA AND NACL SUBSTRATES

Three-dimensional Pd particles were prepared by heteroepitaxial growth on NaCl (001) and alpha-Al2O3 (0001) substrates. During the depositio n the particle structure and orientation were characterized by reflect ion high energy electron diffraction. It was shown that the particle e pitaxial planes conserved the substrate surface symmetry - hexagonal o r cubic. A CCD camera and a computer data treatment system were used f or precise investigation of lattice parameter variation given by the p article interaction with the substrates. It was found that generally t he lattice parameter parallel to the substrate remained constant due t o the particle accommodation to the substrate while the perpendicular lattice parameter varied with particle size. Particle size was investi gated by transmission electron microscopy.