Published online by Cambridge University Press: 15 February 2011
A special type of high angle grain boundary with mirror symmetry of the crystallographic orientation between the two grains is examined electrically and structurally. Transmission electron microscopy investigations show the nonuniform nature of the grain boundary. Both coherent and incoherent regions are observed along the boundary plane, and the types of dislocations and their densities vary from place to place. Electrical measurements of the boundary properties indicate no measurable barrier height. Heat treatment of the sample in an oxygen atmosphere at 950°C for 30 min did not change the boundary resistance. However, recombination effects are enhanced after boron diffusion. When pulsed laser radiation was used to process this material, it was found that the grain boundary structures were modified by laser-induced surface melting, i.e., incoherent boundaries were converted to coherent boundaries in the melted region.
*Research sponsored by SERI under contract DS-0-9078-1 and by U.S. Department of Energy under contract W-7405-eng-26 with the Union Carbide Corporation.