Two distinct branch–stem interfacial structures of silver dendrites with vertical and slanted branchings

Silver dendrites synthesized by sonoelectrochemical deposition are investigated via transmission electron microscopy (TEM) in order to clarify the formation of specific branching angles. Two kinds of dendrites are found to form simultaneously; one has slanted angles while the other shows orthogonal branching. Investigation of the branch–stem interfacial structures reveals that the vertical branches attach at a characteristic transition layer around the main stem, while the slanted growth involves twinning induced dislocations. It is suggested that oriented attachment of nanoparticles followed by epitaxial growth leads to obliqueness, while crystallization of amorphous phase involving grain rotation and realignment results in vertical branching.