Cold welding of gold nanoparticles on mica substrate: Self-adjustment and enhanced diffusion.
From the images of HR-TEM, FE-SEM, and AFM, the cold welding of gold nanoparticles (AuNPs) on a mica substrate is observed. The cold-welded gold nanoparticles of 25 nm diameters are found on the mica substrate in AFM measurement whereas the size of cold welding is limited to 10 nm for nanowires and 2~3 nm for nanofilms. Contrary to the nanowires requiring pressure, the AuNPs are able to rotate freely due to the attractive forces from the mica substrate and thus the cold welding goes along by adjusting lattice structures. The gold nanoparticles on the mica substrate are numerically modeled and whose physical characteristics are obtained by the molecular dynamic simulations of LAMMPS. The potential and kinetic energies of AuNPs on the mica substrate provide sufficient energy to overcome the diffusion barrier of gold atoms. After the cold welding, the regularity of lattice structure is maintained since the rotation of AuNPs is allowed due to the presence of mica substrate. It turns out that the growth of AuNPs can be controlled arbitrarily and the welded region is nearly perfect and provides the same crystal orientation and strength as the rest of the nanostructures.
National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 088826, Republic of Korea.
Song-Hyun
SH
Cha
College of Pharmacy, Inje University, 197 Inje-ro, Gimhae, Gyeongnam 621-749, Korea.
Youmie
Y
Park
Department of Chemical Engineering, University of Seoul, Seoul, 130-743, Korea.
Jeong Woo
JW
Han
Department of Chemical Engineering, University of Seoul, Seoul, 130-743, Korea.
Kyeounghak
K
Kim
National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 088826, Republic of Korea.
Hyun-Seok
HS
Kim
National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 088826, Republic of Korea.
Hong-Lae
HL
Jang
National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 088826, Republic of Korea.
Seonho
S
Cho