الفهرس 
1- Introduction.Only 14 pages are availabe for public view
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Abstract
The X-ray diffraction pattern of the two system Se80S20-xBx and Te80S20-xBx where
(x=0,2.5,5 and B=In or As) was confirm the amorphous nature of the thin film of all samples. The
addition of In or As on the expense of S confirm this result. Also, the non-uniformity of SEM
micrographs confirm the amorphous nature of the samples under test. The SEM micrographs of all
samples after addition of In or As on the expense of S and even the addition of Er cover layer reveals
no change in the amorphous structure. The thermal differential analysis (DTA) of the system
Se80Sx-20Bx proves that the glass transition range is wide. This range becomes narrow as In or As
replacing partially S. The addition of In on the expense of S reduces this range to be 150C-200C.
Replacing In by As this range becomes only one degree. The crystallization temperature (TC) of the
sample Se80S20 was 2330C. The addition of In to Se80S20 on the expense of S reduced TC to be in the
range 2060C- 2110C depending on the In ratio. Replacing In by As with the same ratio decreases TC
to be 1800C and 1400C . The melting temperature range was 300C(5300C-5600C) for the sample
Se80S20. This range decreased to be 15-200C as In replacing S partially.
The thermal differential analysis (DTA) for system Te80S20-xBx where (x=0,2.5,5 and
B=In or As) shows that the glass transition range for Te80S20was 150C(119-1340C). This
range reduced to be 80C as 2.5 at % In added on the expense of S. The replacement of In
by As reduced this range to be 2-30C depending on the As ratio. The crystallization
temperature TC of Te80S20 was 1650C. This temperature increased to be 2770C as 2.5 at %
In added on the expense of S. The replacement of In by As leads to increase Tc to be in the
range 233-2500C depending on the As content.
Generally, the observed shrink of the glass transition range for the two systems give chance
to produce optic fiber cables in the amorphous state, saving costs. The high melting
temperature (Tm) keep the optic fiber cable away from distortion under the environmental
factors and earth movers. Accordingly, these cables can serve the international net
communication well.
The nonlinear variation of the transmission (T) and reflection (R) as a function
of wavelength ( ) in the spectral range 200nm 2500nm for thin film samples of the two
system Se80S20-xBx and Te80S20-xBx where (x=0, 2.5, 5 and B=In or As) were recorded.
The maximum transmission intensity for the system Se80S20-xBx where (x=0, 2.5, 5 and
B=In or As) was 85% at visible and infrared regions. The top of the transmission peak was
at the wavelength 1500nm for Se80S20 sample. The addition of 2.5 at % In on expense of
S, leads to the appearance of plateau at a wavelength range 1100nm-2500nm. Increasing
In content to 5 at %, shift the maximum transmission peaks toward long wavelength
(Red shift) and located at wavelength 1750nm. Replacing In by As with different ratio, the
maximum transmission peak suffered from blue shift.
On the other hand, the reflected light intensity was 45 % for the sample Se80S20 at the
locations 500nm,900nm and 2100nm. The addition of 2.5 at % In increase the reflection to
50% at the location 500nm and change to be 40% at locations 900nm and1400nm.
Increasing In content to 5 at %, keep the reflected light intensity 40% at locations
900nm,1400nm and 2100nm. Replacement In by 2.5 at % As on expense of S, leads to
shift the reflected peak toward short wavelength (blue shift). Increasing As content to 5 at
%, increase the blue shift of the reflected light be peak to appear at the locations 700nm
and 900nm with intensity 60%. The addition Er cover layer leads to appear transmission
plateau with intensity 80 % for Se80S20Er and Se80S17.5In2.5Er samples and 60% for the
sample Se80S15In5Er.
The absorption coefficient was zero at low photon energy, high value at high photon
energy, and moderate values at visible region. The addition of In or As on expense S, lead
to decrease the absorption coefficient. This decrement was more detectable in case of
adding As. The addition of Er cover layer leads to decrease the absorption coefficient of
all sample. The zero or negative value of the extinction coefficient means that very smooth
surfaces of the samples under test.
The light transmission through the samples of the system Te80S20-xBx where (x=0,2.5,5 and
B=In or As) is high during the infrared region. This was clear after the addition of In or As
on expense of S. The addition of Er cover layer decreases the transmission light through all samples. The intensities of the light reflection peaks of the sample Te80S17.5As2.5 were
70% at the wavelength 850nm. The addition of Er cover layer increases this value. The
values of the absorption coefficient were very small at infrared region, moderate at visible
region and very high at ultraviolet region. The addition of Er cover layer keep this behavior
as it is. The addition of In or As on expense of S, decrease the Urbach tail length and
decrease the optical energy gap width. Both of Urbach tail length and optical energy gap
decreased more by the addition of Er cover layer. The addition of In or As increase the
refractive index of all samples. The maximum refractive index was high for Te80S17.5As2.5
before and after the addition Er cover layer. The extinction coefficient decreases in steps
for all samples to zero values or less during infrared region.
The microhardness of the samples of the two system Se80S20-xBx and Te80S20-xBx where
(x=0,2.5,5 and B=In or As) was increased by increasing the applied test load. The addition
of In or As on expense of S, keeps the microhardness behavior the same. The application
of Mayer law confirms that, the microhardness of these systems follow reverse indentation
size effect (RISE). This was revealed as the obtained values of Mayer exponent was greater
than the value two. Using indentation induced cracking (IIC) model, ensure the generation
of micro-cracks. The behavior of the calculated elastic moduli confirms these results.
The Ac conductivity, dielectric constant and dielectric loss of thin film samples of two
system Se80S20-xBx and Te80S20-xBx where (x=0,2.5,5 and B=In or As) were examined
during the frequency range 0.1-107 Hz and the temperature range 233-363 K. The
experimental results show that the Ac conductivity increases with the frequency and
follows the power law s where S<1 and the value of S decreases with increasing the
temperature. The addition of In to Se80S20 sample with different ratios decreases the Ac
conductivity. The same behavior of Ac conductivity is shown for samples Te80S20 and
Te80S17.5As2.5. Also, the Ac conductivity of the thin films samples was increased with
temperature.
The dielectric constant of all samples decreases with frequency and increases with
temperature.
The addition of In or As on the expense of S keep the dielectric constant behavior as it is,
but increases its values. The dielectric loss behaves like, the dielectric constant with
temperature and with frequency.
Generally, the obtained unique structure, thermal stability, physical, mechanical and
electric, dielectric properties supports the use of the chalcogenide material under test as
optical fiber cables.