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Band gap

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Full-Text Articles in Physics

A Dft Study On The Electronic Structure Of Tungsten Trioxide Polymorphs, Masoud Mansouri, Tahereh Mahmoodi Jan 2017

A Dft Study On The Electronic Structure Of Tungsten Trioxide Polymorphs, Masoud Mansouri, Tahereh Mahmoodi

Turkish Journal of Physics

Tungsten trioxide ($WO_{3})$ is an intermediate product in the recovery of tungsten from its minerals. Recently, it has attracted increasing attention due to its exclusive structural properties and its high potential in electronic applications. The crystal lattice of tungsten trioxide is highly dependent on temperature. In this paper we investigated the equilibrium structure of tungsten trioxide in four crystal systems, i.e. monoclinic system, tetragonal system, orthorhombic system, and cubic system. We did our first principle calculations using a pseudopotential model based on the spin dependent density functional theory and implementing generalized gradient approximation for exchange correlation energy. In each case, …


Deposition And Characterization Of Pbo--Pbs Multilayer Thin Films By Solution Growth Technique, Dominic Eya Jan 2014

Deposition And Characterization Of Pbo--Pbs Multilayer Thin Films By Solution Growth Technique, Dominic Eya

Turkish Journal of Physics

PbO-PbS thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. PbO thin films were deposited from the solution of lead nitrate (Pb(NO_3)_2) and sodium hydroxide (NaOH). Ethylenediaminetetraacetate (EDTA) served as the complexing agent. Some of the PbO films were used as substrate for the deposition of PbS. The PbS was deposited from alkaline solution of lead nitrate and thioacetamide. Triethanolamine was used as the complexing agent. Some of the films were subjected to thermal treatment after deposition. Energy dispersive X-ray fluorescence analysis confirmed the presence of Pb and S in the PbS thin films, while …


Hydrogen Implantation Effects On The Electrical And Optical Properties Of Inse Thin Films, Atef Fayez Qasrawi, Khaled Faisal Ilaiwi, Antonio Polimeni Jan 2012

Hydrogen Implantation Effects On The Electrical And Optical Properties Of Inse Thin Films, Atef Fayez Qasrawi, Khaled Faisal Ilaiwi, Antonio Polimeni

Turkish Journal of Physics

The effects of hydrogen ion implantation on the structural, electrical and optical properties of amorphous InSe thin films have been investigated. X-ray diffraction analysis revealed no change in the structure of the films. An implantation of 7.3 x 10^{18} ions/cm^2 decreased the electrical conductivity by three orders of magnitude at 300 K. Similarly, the conductivity activation energy, which was calculated in the temperature range of 300-420 K, decreased from 210 to 78 meV by H-ion implantation. The optical measurements showed that the direct allowed transitions energy band gap of amorphous InSe films has decreased from 1.50 to 0.97 eV by …


The Study Of Copper Zinc Sulphide (Cuzns_2) Thin Films, Chidi Chukwuemeka Uhuegbu, Elisha Bamidele Babatunde, Cornelius O. Oluwafemi Jan 2008

The Study Of Copper Zinc Sulphide (Cuzns_2) Thin Films, Chidi Chukwuemeka Uhuegbu, Elisha Bamidele Babatunde, Cornelius O. Oluwafemi

Turkish Journal of Physics

Thin films of CuZnS_2 were successfully deposited on glass substrates from aqueous solution of copper chloride in which EDTA and TEA were used as complexing agents. The optical and solid state properties were studied include: absorbance, transmittance, reflectance, extinction coefficient, refractive index, absorption coefficient, optical conductivity, dielectric constants. The direct and indirect band gaps obtained ranges from 2.2 eV to 2.4 eV for direct band gap and 0.4 eV to 0.9 eV for indirect band gap. The possible applications were also mentioned.


Preparation And Study Of The Structural, Optical And Electrical Properties Of Cu(In,Ga)Se_2 Thin Films, Athar Javed Jan 2007

Preparation And Study Of The Structural, Optical And Electrical Properties Of Cu(In,Ga)Se_2 Thin Films, Athar Javed

Turkish Journal of Physics

Thin film samples of Cu(In,Ga)Se_2 (CIGS) were prepared at room temperature by physical vapor deposition (PVD) technique using resistive heating method onto soda lime glass substrates. Deposition conditions were same for all the samples. The prepared samples were annealed in vacuum at temperature of 200 °C for 5, 10, 15, 30 and 60 minutes and were characterized structurally, optically and electrically. The structural analysis indicate the partial formation of quaternary CIGS compounds for the samples which were annealed in vacuum at 200 °C for 30 and 60 minutes. XRD analysis indicate that there is a continuous growth and improvement in …


Effect Of Thermal Annealing On The Band Gap And Optical Properties Of Chemical Bath Deposited Znse Thin Films, F. I. Ezema, A. B. C. Ekwealor, R. U. Osuji Jan 2006

Effect Of Thermal Annealing On The Band Gap And Optical Properties Of Chemical Bath Deposited Znse Thin Films, F. I. Ezema, A. B. C. Ekwealor, R. U. Osuji

Turkish Journal of Physics

Zinc selenide (ZnSe) thin films were deposited on glass substrate using the chemical bath deposition method at room temperature from aqueous solutions of zinc sulphate and sodium selenosulfate in which sodium hydroxide was employed as complexing agents. The `as-deposited' ZnSe thin films are red in color and annealed in oven at 473 K for 1 hour and on a hot plate in open air at 333 K for 5 minutes, affecting the morphological and optical properties. Optical properties such as absorption coefficient \alpha and extinction coefficient k, were determined using the absorbance and transmission measurement from Unico UV-2102 PC spectrophotometer, …