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Article
Illumination and Dark Current-Voltage Characteristics of Polymer-Silicon Heterojunction Solar Cells

Author: H.M. Mikhlif
Journal: Iraqi Journal of Applied Physics Letters الرسائل العراقية في الفيزياء التطبيقية ISSN: 1999656X Year: 2009 Volume: 2 Issue: 1 Pages: 15-18
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, polymer-on-silicon solar cells were fabricated by coating different silicon substrates with conductive polyaniline layers. Different substrates with different resistivities were used to control the diffusion length of such configurations. Electrical measurements were performed in both illumination and dark conditions to study the characteristics of photogenerated carriers in the polymer layer contributing to the output of such solar cells. They show good agreement with the “hole mobility only” model for intensities ranging from 1% of AM1.5 up to AM1.5. In addition to low cost fabrication and less-complex technology, such design interestingly compete the conventional and advanced configurations of solar cells.


Article
Linear Adaptive Antenna Array Geometry Effects on Radiation Pattern

Authors: A.H. Sallomi --- H.M. Mikhlif --- S.R. Salim
Journal: Iraqi Journal of Applied Physics Letters الرسائل العراقية في الفيزياء التطبيقية ISSN: 1999656X Year: 2010 Volume: 3 Issue: 1 Pages: 3-6
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

Over the last few years, the number of subscribers to wireless services has increased at an explosive rate. Smart-antenna technology compared to conventional antenna has the ability to increase the number of simultaneous users, and satisfy the requirements of spectral efficiency, and coverage in wireless communication systems. In this paper the radiation pattern and performance of linear smart antenna array is investigated by considering multiple directions of arrivals of signals. The simulations done confirmed that smart antenna systems using Least Mean Square (LMS) algorithm are able to adjust their pattern to enhance desired signals, and reduce interference. The results also show that smart antenna radiation patterns are related to the number of elements in the array, the inter-element spacing, and amplitude distribution.


Article
Effect of Oxygen Quencher on Absorption and Fluorescence Spectra of Rhodamie-6G and Rhodamine-B Dyes in Ethanol Solvent

Authors: H.M. Mikhlif --- M.T. Hussein --- S.J. Lafta
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2005 Volume: 1 Issue: 1 Pages: 20-24
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, absorption and fluorescence spectra of R6G and RB laser dyes were studied. Different concentrations of (1-4)x10-6 mole/liter were used to solve these dyes in an organic solvent such as ethanol. Absorption spectrum of n→S* transition was determined as well as fluorescence spectrum in presence and absence of O2. It was observed that presence of O2 did not affect absorption spectra of both dyes because it has no absorption in the range studied. On the other side, intensity of fluorescence increased as O2 was removed from solvent in both cases of ethanol. Presence of O2 affects fluorescence quantum efficiency and lifetime due to collision with dye molecules. Finally, it was declared that the effect of O2 decreases as the concentration does. This may be attributed to the decrease in collision probability between O2 and dye molecules.


Article
Temperature Dependency of Hall Coefficients in Cadmium Oxide Thin Films Prepared by Thermal Evaporation Technique

Authors: H.M. Mikhlif --- A.M. Raouf --- A.D. Nusaif
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2009 Volume: 5 Issue: 4 Pages: 27-30
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

In this work, the temperature dependencies of Hall coefficients in cadmium oxide thin films prepared by thermal evaporation technique. These coefficients included temperature-dependent Hall coefficient, logarithmic Hall coefficient and Hall mobility. Results showed that the extrinsic conduction prevails in studied samples and impurity atoms introduce energy levels within the energy gap and act as donors. The activation energy of the impurities generally ranged between 0.020eV and 0.070eV. An increase of carrier mobility with temperature was observed then it decreased in higher temperature due to lattice scattering of charge carriers. The values of optical bandgap ranged between 2.90eV and 3.30eV, which is in a good agreement with the those obtained for bulk CdO:Sn samples.

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