Complete replacement of metal in metal oxide nanowires via atomic diffusion: In/ZnO case study.
Atomic diffusion is a fundamental process that dictates material science and engineering. Direct visualization of atomic diffusion process in ultrahigh vacuum in situ TEM could comprehend the fundamental information about metal-semiconductor interface dynamics, phase transitions, and different nanostructure growth phenomenon. Here, we demonstrate the in situ TEM observations of the complete replacement of ZnO nanowire by indium with different growth directions. In situ TEM analyses reveal that the diffusion processes strongly depend and are dominated by the interface dynamics between indium and ZnO. The diffusion exhibited a distinct ledge migration by surface diffusion at [001]-ZnO while continuous migration with slight/no ledges by inner diffusion at [100]-ZnO. The process is explained based on thermodynamic evaluation and growth kinetics. The results present the potential possibilities to completely replace metal-oxide semiconductors with metal nanowires without oxidation and form crystalline metal nanowires with precise epitaxial metal-semiconductor atomic interface. Formation of such single crystalline metal nanowire without oxidation by diffusion to the metal oxide is unique and is crucial in nanodevice performances, which is rather challenging from a manufacturing perspective of 1D nanodevices.
Department of Materials Science and Engineering and §Department of Physics, National Tsing Hua University , Hsinchu 30013, Taiwan.
Shau-Chieh
SC
Wang
Ming-Yen
MY
Lu
Afsal
A
Manekkathodi
Pei-Hsuan
PH
Liu
Hung-Chiao
HC
Lin
Wun-Shan
WS
Li
Te-Chien
TC
Hou
Shangjr
S
Gwo
Lih-Juann
LJ
Chen