A novel method for realization of nickel silicide nanosheets with advanced morphology and photoemission

摘要

Morphologically controlled nanostructures have been increasingly important because of their strongly shape dependent physical and chemical properties. Formation of nanoscale silicon based structures that employ high levels of strain, intentional, and unintentional twins or grain boundaries can be dramatically different from the commonly conceived bulk processes. We report, realization of highly crystallographic 3D nanosheets with unique morphology and ultra-thin thickness by a stress-induced oriented-diffusion method, based on plasma processing of metal layer deposited on Si substrate and its post deep reactive ion etching. Annealing in plasma ambient creates rod-like metal alloy precursors which induce stress at its interface with Si substrate due to the mismatch of lattice constants. This stress opens facilitated gateways for orientated-diffusion of metal atoms in <110> directions and leads to formation of NSs with [111] crystalline essence. Nanosheets are mainly triangular, hexagonal or pseudo hexagonal in shape and their thicknesses are well controlled from several to tens of nanometers.