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Article Citation - WoS: 8Citation - Scopus: 9Structural and Optoelectronic Properties of Cds/Y Thin Films(Elsevier Science Sa, 2019) Qasrawi, A. F.; Abed, Tamara Y.In the current study, the structural, optical, photoelectrical and electrical properties of CdS/Y/CdS thin films are investigated. The current design include the evaporation of a layer of 70 nm thick yttrium between two layers of CdS. Each CdS layer is of thickness of 500 nm. It is observed that the yttrium slab increased the microstrain, defect density, stacking faults and decreased the grain size and redshifts the indirect allowed transitions energy band gap of CdS. In addition an enhancement by similar to 5 times in the light absorbability is detected at 1.74 eV. The enhanced absorbance results in increasing the photocurrent by similar to 21 times and changed the recombination mechanism from a trap assisted recombination to supralinear recombination mechanisms. Moreover, the ac signal analysis in the frequency domain of 10-1800 MHz has shown that the yttrium forces the CdS to exhibit negative capacitance effect and make it behave as band stop filter with notch frequency of 1520 MHz. The quality of the CdS/Y/CdS films as microwave cavities are screened by the evaluation of the return loss which revealed good features of the nanostructured films as microwave receivers.Article Citation - Scopus: 11Cd-Doping Effects on the Properties of Polycrystalline Α-In2se3 Thin Films(Wiley-VCH Verlag GmbH, 2002) Qasrawi,A.F.The X-ray diffraction has revealed that the polycrystalline hexagonal structured α-In2Se3 thin films grown at substrate temperature of 200°C with the unit cell parameters a=4.03°A and c=19.23°A becomes polycrystalline hexagonal structured InSe with a unit cell parameters of a=4.00°A and c=16.63°A by Cd-doping. The analysis of the conductivity temperature dependence in the range 300-40 K revealed that the thermionic emission of charged carriers and the variable range hopping are the predominant conduction mechanism above and below 100 K, respectively. Hall measurements revealed that the mobility is limited by the scattering of charged carriers through the grain boundaries above 200 K and 120 K for the undoped and Cd-doped samples, respectively. The photocurrent (Iph) increases with increasing illumination intensity (F) and decreasing temperature up to a maximum temperature of ∼100 K, below which Iph is temperature invariant. It is found to have the monomolecular and bimolecular recombination characters at low and high illumination intensities, respectively. The Cd-doping increases the density of trapping states that changes the position of the dark Fermi level leading to the deviation from linearity in the dependence of Iph on F at low illumination intensities.
