Intrinsic Lattice Relationship of Catalyst/Nanowire Interfaces by Heating High-Resolution Transmission Electron Microscopy

The clarification of intrinsic, atom-level catalyst/nanowire interfacial microstructures is of great help in understanding the underlying catalytic mechanisms and realizing controllable nanowire growth. Herein, we investigate the interfacial microstructures and lattice relationship between body-centered cubic (bcc) superionic-phase alpha-Ag2Se and face-centered cubic (fcc) zinc blende (ZB) ZnSe for the Ag2Se/ZnSe catalyst/nanowire growth system by high-resolution imaging in heating high-resolution transmission electron microscopy (heating HRTEM). It is found that the bcc alpha-Ag2Se (110) and fcc ZB-ZnSe (111) pair planes make up the most preferred adjoining interface, which theoretically have a considerable lattice misfit but probably exhibit a nearly complete, two-dimensional (2D) planar coherent relationship through the lattice straining of the ZB-ZnSe (111) plane along a specific crystallographic orientation (i.e., [110]). A reasonable atomic model, consistent with the heating HRTEM results, is presented to demonstrate the strained, 2D coherent alpha-Ag2Se/ZB-ZnSe catalyst/nanowire interface. Meanwhile, we rationally explain the formation of this specific alpha-Ag2Se (110)/ZB-ZnSe (111) interface from the views of the atomic closest packing and nanowire growth habits, the interfacial energy and activity, the small size effect on lattice strain and deformation, as well as the effect of the solubility of the nanowire in the catalyst on interdiffusion.