Iraqi Journal of Physics

In this work, we study the effect of doping Sn on the structural
and optical properties of pure cadmium oxide films at different
concentrations of Tin (Sn) (X=0.1, 0.3 and 0.5). The films prepared
by using the laser-induced plasma at wavelength of laser 1064 nm
and duration 9 ns under pressure reached to 2.5×10-2 mbar. The
results of X-ray diffraction tests showed that the all prepared films
are polycrystalline. As for the topography of the films surface, it was
measured using AFM, where the results showed that the grain size
increases with an increase in the percentage of doping in addition to
an increase in the average roughness. The optical properties of all
films have also been studied through the absorbance spectrum of the
range of the wavelength (350 -1100) nm, where the optical energy
gap was direct transitions it was found that the value of the optical
energy gap increased with increasing the doping This increase can be
interpreted as a result of the so-called Borsstein-Moss displacement,
because because the lower levels of the conduction beams are full of
electrons, the electrons need more energy to travel, so it seems as if
the energy gap increases.

Numerical analysis predicts that continuous-wave (CW) Raman
lasing is possible in Silicon-On-insulator (SOI) nano-waveguides,
despite of presence of free carrier absorption. The scope of this paper
lies on lasers for communication systems around 1550 nm
wavelength. Two types of waveguide structures Strip and Rib
waveguides have been incorporated. The waveguide structures have
designed to be 220 nm in height. Three different widths of (350, 450,
1000) nm were studied. The dependence of lasing of the SOI Raman
laser on effective carrier lifetime was discussed, produced by two
photon absorption. At telecommunication wavelength of 1550 nm,
Raman lasing threshold was calculated to be 1.7 mW in Rib SOI
waveguide with dimensions width (W= 450 nm) and Length
(L= 25 mm). The obtained Raman lasing is the lowest reported value
at relatively high reflectivities. Raman laser in SOI nano-waveguides
presents the important step towards integrated on-chip optoelectronic
devices.

X-ray emission contains some of the gaseous properties is
produced when the particles of the solar wind strike the atmosphere
of comet PanSTARRS Comet. The data collected with NASA
Chandra X-ray Observatory of the two comets, C/2012 S1 (also
known as Comet (PanSTARRS)) was used in this study. The real
abundance of the observed X-ray spectrum elements has been
extracted by a new simple mathematic model. The study found some
physical properties of these elements in the comet’s gas such as a
relationship between the abundance with emitted energy. The
elements that have emission energy (2500-6800) eV, have abundance
(0.1-0.15) %, while the elements that have emission energy (850-
2500) eV and (6800-9250) eV have abundance (0.2-0.3) %. The
relation between interacted energy and atomic number is formed two
sets. The interacted energy of each element is increased as the atomic
number increased. This case has been seen in both comets.

In this research, analytical study for simulating a Fabry-Perot
bistable etalon (F-P cavity) filled with a dispersive optimized
nonlinear optical material (Kerr type) such as semiconductors Indium
Antimonide (InSb). An optimization procedure using reflective
(~85%) InSb etalon (~50µm) thick is described. For this etalon with
a (50 µm) spot diameter beam, the minimum switching power is
(~0.078 mW) and switching time is (~150 ns), leading to a switching
energy of (~11.77 pJ) for this device. Also, the main role played by
the temperature to change the etalon characteristic from nonlinear to
linear dynamics.

Chemical bath deposition (CBD) was used to synthesize ZnO
nanorods (NRs) on glass and fluorine_doped tin oxide (FTO)
substrates. X-ray diffraction was performed to examine the
crystallinity of ZnO nanorod. Results showed that ZnO NRs had a
Wurtzite crystal structure and grew along the (002) orientation. Field
emission scanning electron microscopy (FESEM) images showed the
glass sample had rod-like structure distribution with (50 nm)
diameter and average length of approximately (0.7 µm), whereas the
FTO-coated glass sample had 25 nm diameter and average length of
approximately 0.95 µm. The direct optical transition band gaps of the
glass and FTO_coated glass samples were 3.97 and 4.13 eV
respectively. The structural and optical properties of the synthesized
ZnO NRs were described. The grown ZnO NRs have good optical
properties. It was noticed through the tests that ZnO NRS prepared
on FTO substrates is better than ZnO NRS prepared on glass
substrates made using the same technique.

The absorption spectrum for three types of metal ions in different
concentrations has been studying experimentally and theoretically.
The examination model is Gaius model to find the best fitting curve
and the equation controlled with this behavior. The three metal ions
are (Copper chloride CuCl3, Iron chloride Fe2Cl3, and Cobalt chloride
CoCl3) with different concentrations (10-4, 10-5, 10-6, 10-7) gm/m3.
The spectroscopic study included UV-Visible and fluorescence
spectrum for all different concentrations sample. The results refer to
several peaks that appear from the absorption spectrum in the high
concentration of all metal ions solution. The multiple absorption
peaks continued even at the lowest concentration in the iron ion
solution. Fluorescence spectrum shows intensive stimulating of the
radiation strength was perceived in the manifestation of Cu+2, Co+2
and Fe+3. From modeling investigation, there are converge between
experimental and theoretical results of the fluorescence spectrum for
metal ions. Furthermore, identity and convergence which defined as
(r2), are on average (0.995)

In this study, the effect of grafting with magnesium (Mg) ratios
(0.1, 0.3, 0.5) on the structural and optical properties of cadmium
oxide films (CdO) was studied, as these films were prepared on glass
bases using the method of pulse laser deposition (PLD). The
crystallization nature of the prepared films was examined by X-ray
diffraction technique (XRD), which showed that the synthesis of the
prepared films is polycrystalline, and (AFM) images also showed
that the increased vaccination with magnesium led to an increase in
the grain size ratio and a decrease in surface roughness, The
absorption coefficient was calculated and the optical energy gap for
the prepared thin films .It was found the absorption increases and the
energy gap decreases with the increase of doping ratio.

Dust storms are a natural phenomenon occurring in most areas of
Iraq. In recent years, the study of this phenomenon has become
important because of the danger caused by increasing desertification
at the expense of the green cover as well as its impact on human
health. In this study is important to devote the remote sensing of dust
storms and its detection. Through this research, the dust storms can
be detected in semi-arid areas, which are difficult to distinguish
between these storms and desert areas. For the distinction between
the dust storm pixels in the image with those that do not contain dust
storm can be applied the Normalized Difference Dust Index (NDDI)
and Brightness Temperature variation (BTV). MODIS sensors that
carried by the Terra and Equa satellite images have been used in
different bands and different resolution and the cases studied in
1/9/2015, 16/6/2016/ 20/2/2016.

In this work, spinel ferrites (NiCoFe2O4) were prepared as thin
films by dc reactive dual-magnetron co-sputtering technique. Effects
of some operation parameters, such as the distance between
electrodes (inter-electrode distance), and preparation conditions such
as gas mixing ratio of argon and oxygen, on the structural and
spectroscopic characteristics of the prepared samples were studied.
For samples prepared at an inter-electrode distance of 5 cm, only one
functional group of OH- was observed in the FTIR spectra as all
bands belonging to the metal-oxygen vibration were observed.
Similarly, the XRD results showed that decreasing the pressure of
oxygen in the gas mixture leads to grow more crystal planes in the
samples prepared at an inter-electrode distance of 5 cm. The energy
band gap was determined for the sample prepared with a mixing ratio
of 65:35 and found to be 2.7, 2, and 3.35 eV for direct allowed, direct
forbidden, and indirect allowed transitions, respectively. The high
structural purity was confirmed as no traces for any elements other
than Co, Ni, Fe, and O were found in the final samples.