Publications in Scientific Journals:

S.T. Nakagawa, K. Ikuse, T. Ono, H.J. Whitlow, G. Betz:
"Crystallographic analysis of extended defects in diamond-type crystals";
Nuclear Instruments & Methods in Physics Research Section B, 232 (2005), 322 - 326.

English abstract:
To investigate irradiation-induced Si amorphization during its initial
stages, we have performed a classical molecular-dynamics (MD) calculation
for the case of self-irradiation by 5 keV ions at a low temperature of 100

We examined the geometry of self-interstitial atom (SIA) clusters using the
pixel mapping (PM) method, on the output data of MD calculations. Perfect
crystalline silicon (c-Si) is amorphized by self-irradiation, and we observe
that many SIA are produced. During sequential self-irradiation, the most
frequently observed species were isolated SIA, i.e. I1 (monomer). The
fractions of SIA clusters decreased as I2 (dimer), I3 (trimer), and I4
(tetramer) clusters, respectively. For I2 clusters, the 1 1 0 oriented I2s
were the dominant I2 species, which agree with previous predictions based on
static calculations. Nevertheless, other I2s with different orientations
were also significant. Some of them have been proposed as intermediate I2s
in forming dislocations. The present results imply that irradiation-induced
SIAs play an important role in the triggering of amorphization, and MD
combined with PM can reveal the intermediate processes underlying
extended-defect formation.

Keywords: Amorphization; c-Si; Self-irradiation; Long-range-order
interaction; Self-interstitial atom cluster; Molecular-dynamics

PACS: 61.50.Ah; 31.15.Qg; 68.35.Rh; 61.72.y

Online library catalogue of the TU Vienna:

Created from the Publication Database of the Vienna University of Technology.