In this research we studied the relationship between the optical conductivity Ϭop and
photon energy (hν), the absorbance coefficient (α), transmittance (T), the refractive index
(no), and the real part and imaginary part of dielectric constant (εr,
εi), the spinning velocity
of deposition device (v), for a specific wave length (600nm), for a pure thin film prepared
from an organic polymer material, Polystyrene (PS), by spin coating technique, on three
velocities ( 1000-2000-3000)RPM, in room temperature and 1atm.
It was shown that the PS film is a transmittive film with a transmittance values
reach ( 85 – 90 )% in the infrared region, and the optical conductivity Ϭop increased with
the photon energy, and for the velocity 1000RPM it took the highest value ( 1.67 X
1014 )1/sec, at the photon energy (hν =3.1 ev) and the wave length ( λ= 400nm ),
which means that the optical conductivity Ϭop is active in the visible region, and also it
decreases with the spinning velocity.
The values of energy gap for allowed direct transitions were (2.5ev), (2.4ev), (2.3ev)
for the films prepared on 1000RPM, 2000RPM, 3000RPM, and for the forbidden direct
transitions were (2.3ev), (2.2ev), (2.1ev) respectively .
The biggest value of Urbach energy Eu was (163mev) on the velocity 1000RPM and
the lowest value was (109mev) on the velocity 3000RPM.
In this paper samples of poly vinyl chloride PVC ,pure, irradiated
with Gama rays, were prepared by casting method in room
temperature and light, and under atmosphere pressure.
It was observed from this research that irradiation made real effect
on some of the studied optical properties, the irradiation increased
the transmittance while the electronic transitions kind remained
indirect before and after the irradiation.
Monodispersed CdSe Nanorods nanoprticles with sufficient luminescence intensity have been prepared by chemical method in solution phase. CdSe as a core covered by Olic acide as an organic capping agent. The nanodots size obtained by two methods: dir
ectly from high resolution transmission electron microscopy (TEM) and using absorption peaks comparison with literature, the two methods are in good agreement. The optical properties and the luminescence intensity as a function of CdSe NRs concentration and the type of solvent (Chloroform and Toluene) have been investigated. The intensity of photoluminescence peak decreases and the peak shifts toward the blue energy side as the concentration reduced. The results show the relation between the polarity, the effect of surface, concentration, and the quantum effect on the optical properties.
A study of surface chemical composition has been performed by using Auger Electron Spectroscopy (AES) for ZnO layers grown by Atomic Layer Deposition (ALD) procedure.Elements on surface of materials were identified,and, an atomic concentration of ele
ments on surface was determinate. Onlysmall amount of carbon or carbon compounds detected, easily removed by argon ion sputtering. Also, long argon ion sputtering partly depleted surface of oxygen.
Monodispersed CdSe nanoparticles with sufficient luminescence intensity have been prepared by chemical method in solution phase, and in two forms: CdSe as a core covered by Olic acide as an organic capping agent, while the second form is CdSe as a co
re covered by a layer of CdS (CdSe/CdS core shell). The nanodots size obtained directly from high resolution transmission electron microscopy (TEM) and absorption peaks using Paul Mulvaneys formula are in good agreement. The optical properties and the luminescence intensity as a function of CdSe concentration and the type of solvent have been investigated. The intensity of photoluminescence peak decreases and the peak shifts toward the blue energy side as the concentration reduced
In this paper we present the structural, optical and electrical characteristics of ZnO thin films grown for different parameters by the atomic layer deposition (ALD) method. The films were grown on glass and silicon substrates at low temperatures. We
used diethyl-zinc (DEZn) and deionized water as zinc and an oxygen sources, respectively. Measurements of surface morphology, photoluminescence at room temperature (RT PL) and Hall Effect were made for ZnO layers. The films obtained at 130°C show the highest carrier concentration (1.1×1019 cm-3) and the lowest resistivity (2.84×10-2 Wcm). The films exhibit mobility up to 19.98 cm2/Vs that we associate to the technological process used.
