WEBREVIEW

Treatment of commercial aluminum by Nd:YAG laser

Baziz L. , Nouiri A. — 2015-12-17T09:08:26Z

In this work, two types of commercial aluminum alloys (industrial and recovered aluminum) are studied. The surface is irradiated by Nd : Yag laser (λ = 532 nm, with a pulse duration of 15 ns and an energy of 50 mJ). The experimental results show that the hardness profile can be divided into three regions. The melted area is the hardest region, Then, the hardness decreases sharply in the interface region between the melted area and the heat-affected (...)

- Numero 00 / Aluminum Alloys, Laser treatment, Hardness

Optical and structural study of plastic deformation of single crystals

Arabe L. , Guergouri k. , Hamdellou S. , Harouni S. — 2015-12-17T09:05:12Z

CdTe pure and alloyed with some isoelectronic impurities was found in front of more than twenty years as very promising in optoelectronics. The effectiveness of components based on these materials is strictly related to their quality. It is in this context that our work. The objective in this study is to see the effect of plastic deformation of crystals of CdTe and CdZnTe on crystallographic and optical properties. The investigation methods are X-rays as a means of crystallographic (...)

- Numero 00 / Dislocations, optical gap, single crystals, CdTe, CdZnTe, plastic deformation, UV-visible.

Study of the performance of ballistic carbone nanotube FETs

Benkara S., Lamamra K. , Rechem Djamil — 2015-12-17T08:58:09Z

Using a two-dimensional (2-D) simulation, we study the impact of varying the nanotube diameter and gate oxide thickness on the performance of a ballistic nanoscale carbon nanotube field effect transistor (CNTFET). Our results show that the nanotube diameter influences the ION/IOFF current ratio ; the drain induced barrier lowering (DIBL), the subthreshold slop as well astransconductance and drain conductance. We also show that these device characteristics are affected by the gate oxide (...)

- Numero 00 / carbon nanotubes, Field- effect transistor, Ballistic, Carbon nanotube diameter, Gate oxide thickness

Toy Model Of Spinfet Transistor

Benhizia K. , Boudine A., Djebbari N. — 2015-12-17T08:52:58Z

The study of spin polarized transport in semiconductors is achieved by the transmission of current in semiconductor devices, our study focuses on spintronics or spin electronics in these devices. We chose the spinFET transistor or the transistor at`spin rotation' as a better implementation because it is a type of HEMT transistor in which we replace the source and drain by ferromagnetic contacts. The source contact acts as a spin polarizer for electrons injected into the conduction channel of (...)

- Numero 00 / Spin polarized transport, spintronic,, spinfet, Semiconducteur

Spin polarized transport in semiconductor

Benhizia K. , Boudine A. , Kallaa L. — 2015-12-17T08:48:05Z

In this paper, we study two-dimensional spin polarized transport in semiconductors. Based on the some semiclassical considerations and taking account of the spin relaxation. We determined the relationship of the polarization as a function of
time and the distance. And we have also established the relationship of the drain current in a 2D channel of a transistor called « spin-FET » where it was matter to highlight this type of transport. This study was crowned with a numerical study of the (...)

- Numero 00 / Spin polarized transport, spintronic,, spinfet, Semiconducteur

Numerical analysis of GaAs MESFETs OPFET

Azizi C. , Hamma I. , Saidi Y. , Zaabat M. — 2015-12-17T08:43:19Z

A Tow dimensional numerical model of channel potential for GaAs MESFET (Metal semiconductor field effect transistor)doped uniformly .the model takes into acount the effects in channel region considering both the photoconductive effect and photovoltaic effect at the gate schottky . the 2-D potential distribution function in the active layer of the divice is solved numerically under dark and illumination (...)

- Numero 00 / 2-D modeling potential distribution, Photodetector, Photovoltage.

Electronic structure calculation of the GaAs/AlAs quantum dot

Brezini A. , Chalabi D. , kanouni F. , Mostefa A., Saidane A., Sekkel N. — 2015-12-17T08:38:53Z

Theoretical investigation of the electronic structure of GaAs/AlAs quantum dots superlattices is presented. We use the envelope function approximation in connection with Kronig-Penney model to calculate the conduction band structure of the cubic quantum dot crystal. . We show that, when quantum dots are separated by a finite barrier and positioned very close to each other so that there is a significant wave function overlap, the discrete energy levels split into three-dimensional minibands. We can control the electronic structure of this artificial quantum dot crystal by changing theirs technological parameters, the size of quantum dots, interdot distances, barrier height, and regimentation. This type of structure provides electronic and optical properties very important that are different to that of bulk and quantum well superlattices. The proposed engineering of three-dimensional minibands in quantum dot crystals allows one to fine-tune electronic and optical properties of such nanostructures.

Elaboration and characterization of zinc oxide varistors

Aida M. S., Beggah Y. , Bouchekhlal A. — 2015-12-17T08:32:32Z

ZnO-based varistors were fabricated by sintering zinc oxide micro crystals with several additives of metal Oxides. The
effect of sintering temperature on varistor properties of (Bi, Co, Cr, Mn, Sb, Al)-doped ZnO ceramics was investigated in the range of 1280–1350 °C. The average grain size increased to 5.13 to 7.88 μm with the increase of sintering temperature. However,
the nonlinear coefficient of this system was nearly constant in the range of sintering temperature. The highest breakdown voltage was 1143.4 v / cm for the varistor sintered at 1350 °C the sample C sintered exhibited the best electrical properties.

Investigation on chemical bath deposited CdS thin films

Abdelmalek N., Attaf N. , Hadjeris L. , Herissi L., Moualkia H. — 2015-12-17T08:29:19Z

This paper presents the effect of solution temperature on optical, electrical and photoconducting properties of CdS films prepared by chemical deposition method. The solution temperatures used varied between 55 and 75 °C. X-ray diffraction
analysis showed that the prepared films have an hexagonal structure with (002) reflection. The transmittance data analysis showed a high transmission coefficient in visible range (85%) and an optical band gap lying between 2 and 2.4 eV. Scanning electron microscopy (SEM) and electrical measurements showed a pronounced effect of the solution temperature on thickness, dark conductivity and photoconductivity to dark conductivity ratio (σphot/σdark) parameters. The evolution of such parameters as a function of temperature are presented and discussed. It was found that the (σphot/σdark) ratio reaches high values of the order of 104 and 105 at 55 and 65 °C, respectively. These results indicate that CdS thin films prepared at these temperatures are convenient for optoelectronic and photovoltaic applications.

Substrate effect temperature on Cu2ZnSnS4 thin films deposited by

2015-12-17T08:22:59Z

Cu2ZnSnS4 (CZTS) thin films are a potential candidate for absorber layer in thin film solar cells. CZTS films were deposited by
spray ultrasonic technique. An aqueous solution composed of copper chloride, zinc acetate, tin chloride and thiourea like
precursors is sprayed on heated glass substrates at various temperatures. The substrate temperature was changed from 280°C to
360°C in order to investigate its influence on CZTS films properties. The DRX analyses indicated that Cu2ZnSnS4 films (...)

- Numero 00 / Thin films, XRD, photoluminescence, CZTS, Transmission., spray technique