PERSONAL DE APOYO
RUNCO Jorge Marcelo
congresos y reuniones científicas
Título:
Dopant location in Mn- and Al-doped iron disilicides
Autor/es:
J. DESIMONI; S. M. COTES; J. MARTÍNEZ; J. RUNCO; M.A. TAYLOR
Lugar:
La Plata
Reunión:
Conferencia; XI Latin American Conference on the Applications of the Mössbauer Effect; 2008
Institución organizadora:
LACAME 08
Resumen:
The strong and continual interest on the ecological-friendly low temperature semicon-
ductor
-FeSi
2
phase, with a wide spectrum of interesting physical properties, rests on
the fundamental issues related to the stability of the phases, growth kinetics, interface
structure, and on the technological applications to microelectronic, thermoelectric, pho-
tovoltaic and optoelectronic. For technological applications, the control of the electrical
conductivity of the system is critical and the intrinsic semiconductor needs to be doped
to form either
n
-type or
p
-type
-FeSi
2
. Additives like Pt, Mn and Al can turn the
material into a
p
-type semiconductor. In spite of the eort performed on the subject, the
doping of the iron disilicide semiconductor phase is still an open question since encloses
intriguing fundamental issues related to dopant location in the two crystallographically
inequivalent Fe sites of the orthorhombic structure of
-FeSi
2
. Then, in the present con-
tribution, iron disilicides of the type Fe
1
x
R
x
Si
2
(R = Mn, Al, 0.00
x
0.12) prepared
by ball milling and subsequent annealed at 1123 K are study using X-ray diraction and
Mossbauer spectroscopy.
Supported by the calculations performed using a model that accounts for the vacancy
concentration, site occupation and sample composition, a preferential substitution of Fe
by Mn atoms at the regular lattice Fe
site II
, in the
-FeSi
2
structure could be inferred
from the present results. Nevertheless, nor replacement of Al atoms in iron sites can
be conjectured from the present results. Although, replacement of Si atoms by Al onescould not be deduced from the XRD patterns