Y. Wu et al., High-resolution transmission electron microscopy study on the anomalous structure of lead nanoparticles with UHV-MBE-TEM system, SURF SCI, 462(1-3), 2000, pp. 203-210
The structure of lead nanoparticles ranging from 2 to 10 nm in diameter was
studied with high-resolution transmission electron microscopy (HRTEM). Lea
d nanoparticles were deposited on a silicon substrate at room temperature a
nd observed without exposure to the air. In addition to face-centered cubic
(fcc), we have found a body-centered tetragonal (bct) structure that has a
space group of I4/mmm with lattice parameters a and c being about 0.33 nm
and 0.62 nm, respectively. This bet structure existed in not only the singl
e crystals and single-twinned particles, but also multiply-twinned particle
s (MTPs. It was found that coexistence of the fee and bet units forms a per
fect MTP structure with fivefold axis. MTPs with sixfold axis were also obs
erved, which is explained properly by the combination of bet structure unit
s with different orientations. (C) 2000 Elsevier Science B.V. All rights re
served.