Electron Diffraction Study of Particle Size in Thin Bi Films Deposited by Evaporation in Vacuum

摘要

Electron diffraction patterns of thin Bi films were studied by the method of microphotometer density curve analysis to determine changes of the film structure with aging and with increase in thickness of the films. All Bi films were deposited on Formvar by evaporation in vacuum. Analysis of the Bi diffraction patterns by comparison with the Formvar pattern as a reference standard indicate that the very thin films (about 20 atom layers or less in thickness) while initially composed of small crystals grow rapidly upon aging into larger crystals. The very thinnest film (about 5 atom layers thick) analyzed exhibited an initial increase in particle size followed by a decrease upon aging, a somewhat anomalous result requiring further confirmation. Increase in particle size with increase in thickness of the Bi films is observed also, although the results of these latter experiments are somewhat irregular.