XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
60
T1: O–18
Infrared studies of the phase transition
in hybride (C
3
N
2
H
5
)2SbF
5
crystal
D. Podsiadła
1
, B. Andriyevsky
2
, and O. Czupiński
3
1
Institute of Experimental Physics, University of Wrocław, M.Born Sq. 9, 50-204 Wrocław, Poland,
e-mail: dorota@ifd.uni.wroc.pl
2
Faculty of Electronics and Computer Sciences, Koszalin University of Technology, Śniadeckich 2,
75-453, Koszalin, Poland
3
Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland
Phase transitions of (C
3
N
2
H
5
)
2
SbF
5
– bis(imidazolium)pentafluoroantimanate (abbreviated as
IPFA) crystal have been investigated by infrared measurements. Differential scanning
calorimetry showed phase transitions (established as an onset of the peak) at 216 K on cooling.
The infrared spectra of powdered IPFA crystal in Nujol and Perfluorolube oil were studied in
the wide range of internal vibration of the (C
3
N
2
H
5
)
2
+
and SbF
5
2–
ions (4000−400 cm
–1
) in the
temperature range between 183 K (154 K in fluorolube) and 300 K. The temperature changes of
wavenumber, half-width, center of gravity and intensity of the bands were analysed to clarify the
cationic and anionic dynamics contribution to the phase transitions mechanisms.
Figure below shows an example of temperature dependence of the mode at 1180 cm
–1
position. The jump in position of this peak occurs near the phase transition (PT) temperature.
This temperature is indicated in Figure 1 by dashed, vertical line.
180
200
220
240
260
280
300
1170
1172
1174
1176
1178
1180
1182
mode 1180 cm
-1
W
a
v
e
n
u
m
b
e
r
[c
m
-1
]
T [K]
Fig. 1. Temperature dependence of the mode at 1180 cm
–1
position.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
61
T1: O–19
The dielectric functions and chemical and atomic compositions of the
near surface layers of implanted GaAs by In
+
ions
M. Kulik
1,2
, D. Kołodyńska
3
, A. Bayramov
4
,
A. Drozdziel
2
, A. Olejniczak
5
, and J. Żuk
2
1
Joint Institute for Nuclear Research, St. 6 Joliot-Curie, Dubna, Moscow reg., Russia, 141980
2
Institute of Physics, Maria Curie-Skłodowska University, Sq. 1 Maria Curie-Skłodowska, 20-031
Lublin, Poland, e-mail: mkulik@hektor.umcs.lublin.pl
3
Faculty of Chemistry, Maria Curie-Skłodowska University, Sq. 2 Maria Curie-Skłodowska, 20-031
Lublin, Poland
4
Institute of Physics, ANAS, AZ-1143, Baku, Azerbaijan
5
Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, Toruń, Poland
The dielectric functions ε(E), atomic surface concentrations and chemical compositions have
been studied in the near surface layers of the implanted GaAs before and after thermal treatment.
The surfaces of semi isolating GaAs have been irradiated by In+ ions with the energy 250 keV
and fluences were in a region from 1×10
13
cm
–2
to 3×10
16
cm
–2
. The irradiated samples were
isobaric annealing at 800°C during 2h. The depth profiles of the atomic surface concentrations
were measured with the help of Rutherford backscattering spectrometry and nuclear reactions
RBS/NR. It was noticed two processes in the all study samples. The first was diffusion indium
atoms to the irradiated surfaces and second effect was change of the surface atomic
concentration of oxygen atoms in the native oxide layers covered the implanted GaAs. The
functions ε(E) were investigated in the photons energy region from 1.3 eV to 5.0 eV. The depth
profiles of ε(E) were obtained of the removable chemical layers for the all study sample. Several
effects were observed in the measured spectra. They were associated with the formation of
amorphous layers and the disappearance of bounds E1 and E1+Δ1 associated with critical points
CP. The reconstruction of these bands has been observed in the spectra collected for the all
samples after thermal treatment. The parameters of these bands were different for the samples
irradiated with different fluences and at various depths from the surface. These effects may be
explained by the reconstruction of the GaAs crystallographic structure damaged in varying
degrees in the implantation process. During the process of thermal annealing InAs was formed
in the near surface layers of the samples implanted with the fluences 3×10
15
cm
–2
, 1×10
16
cm
–2
and 3×10
16
cm
–2
. This effect was noticed during the measurements with the help X-ray
photoelectrical spectroscopy (XPS) of the study samples after the thermal treatment process.
These disordered layers in the implantation process were reconstruction and indium atoms
formed with displacement atoms of GaAs the new chemical compound InAs. In addition, these
processes influenced the formation of the natural oxides of different chemical composition and
different optical constants. It has been found that amounts of InO
2
and relative amounts
Ga
2
O
3
/As
2
O
3
increase in the native oxide layers with the fluences before the thermal treatment
of the samples. It was observed the amounts of Ga
2
O
3
did not change after the thermal annealing
and they were approximately on the same level as before the process. In addition, it was
subordinated that the quantity of As
2
O
5
decreases in the all native oxide layers after the thermal
treatment. The study showed that the use of the methods SE, RBS/NR, and XPS allows for a
more precise definition of the dielectric function of the near surface layers of irradiated GaAs.
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