Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : electrical properties

Preparation and Characterization Study of Porous Silicon Doped with Cu and Ag

U. M. Nayef; A.M. Abdul Hussein; A. J. Kata

Engineering and Technology Journal, 2017, Volume 35, Issue 1, Pages 8-12

In this paper, porous silicon was prepared by using electrochemical etching technique of p-type silicon acceptor, with a resistivity of, using hydrochloric acid with concentration of 24%. The etching current density effect 4, 12, 20mA/cm2 was carried out at constant etching time of 15min. The structural characteristics of the porous silicon and the doped porous silicon were studied and found an expansion in the spectrum of the X-rays and a simple shift in the diffraction angles while maintaining the surface direction (111). The morphological properties were studied using the atomic force microscope which showed pores formation and gives the pore diameter within the range of 19.08 to 44.73nm for the prepared samples. It was also noted that the rate of pore diameter and the thickness of the porous silicon layer increased with increasing etching current density. Electrical characteristics of the nanoscale porous silicon layer and the doped porous silicon with silver and copper showed that Current-Voltage (I-V) characteristics of the prepared samples to be a rectifying behavior. An improvement in the electrical characteristics of the doped porous silicon samples was observed

Investigation of Structural, Optical and Electrical Properties of ZnO Prepared Thin Film by PLD

Samer. Y. Al-Dabag

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 838-847

In this paper , Zinc Oxide (ZnO) films were grown on glass substrates by Pulsed Laser Deposition (PLD) technique at room temperature under the vacuum pressure of 3×10−3 mbar. Employing a Nd:YAG pulses laser at wavelength 1064nm was used in this technique .The effect of number of laser pulses (200,500 and 800) at annealing temperature450C oon the structural, optical and electrical properties was studied.The structure of the ZnO thin films was examined by X-Ray diffraction (XRD), it was found thatZnO thin films arepolycrystalline with many peaks, and the results of Atomic Force Microscopy (AFM) indicated that all films have grain size around 90 nm.The optical properties concerning the photoluminescence (PL) spectra were studied for the prepared thin film. From the PL, the optical gap of the ZnO thin film was determined. The Hall effect measurements confirmed that the ZnO thin films are n-type , While the number of laser pulses is increasing, the charge carriers concentration (n) increases, and Hall mobility (H) decreases.

Effect of additive of CuO and annealing on the Morphological and Electrical Properties of TiO2 by pulse laser deposition

Sabah N. Mazhir; Ghosoun Hamid Ahmed; Noha. H. Harb; A.Abdallah.A

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 895-907

In this paper, Nano crystalline TiO2 and CuO additive TiO2 thin films were successfully deposited on suitably cleaned glass substrate at constant room temperature, and different concentration of CuO (0,5,10,15,20)% wt using pulse laser deposition(PLD) technique at a constant deposition parameter such as : (pulse Nd:YAG laser with λ=1064 nm, constant energy 800 mJ ,with repetition rate 6 Hz and No. of pulse (500).The films were annealed at different annealing temperatures 423K and 523 K. Effect of annealing on the morphological and electrical were studied. Surface morphology of the thin films has been studied by using atomic force microscopes (AFM). AFM measurements confirmed that the films have good crystalline and homogeneous surface. The Root Mean Square (RMS) values of thin films surface roughness are increased with the increase of annealing temperature. Also, The grain size increases with the increasing of concentration of CuO and annealing. The temperature dependence of the electrical conductivity and the activation energy at temperature ranging from (293-473)K of the as-deposited and films annealed at different annealing temperatures have been studied. The results show that as the film concentration of CuO and conductivity increases, while the activation energy(Ea1,Ea2) decreases. Both, the annealing and composition effects on Hall constant, RH, charge carrier concentration (NH), Hall mobility. Hall Effect are studied. Hall Effect measurements show that all films have n- type charge carriers and the concentration and annealing increases carriers concentration while the mobility decreases .

I-V and C-V Characteristics of Porous Silicon Nanostructures by Electrochemical Etching

Fatima I. Sultan; Amna A. Slman; Uday M. Nayef

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 332-338

Porous silicon (PS) layers has been prepared in this work by electrochemical etching (ECE) technique of a p-type silicon wafer with resistivity (1.5-4 Ω.cm) in hydrofluoric (HF) acid of 20% concentration. Various affecting studied etching time (10, 30, and 45 min) and current density (15 mA/cm2). We have study the morphological properties (AFM) and the electrical properties (I-V and C-V).
The atomic force microscopy investigation shows the rough silicon surface, with increasing etching process (etching time) porous structure nucleates which leads to an increase in the depth and width (diameter) of surface pits. Consequently, the surface roughness also increases.
The electrical properties of prepared PS; namely current density-voltage characteristics under dark, show that the pass current through the PS layer decreased by increasing the etching time, due to increase the resistivity of PS layer. The PS layer shows a rectifying behaviour with different rectification ratio. C-V measurements shows that the increase of the etching time decreases the capacitance of the PS layer. This behavior was attributed to the increasing in the depletion region width which leading to the increasing of built-in potential.

Influence of Post- Annealing on The Properties of Cuxs: Al, Fe Films Deposited By C B D

Ali M . Mousa; Abbas F. Sabbar

Engineering and Technology Journal, 2009, Volume 27, Issue 14, Pages 2632-2641

Thin films of copper sulfide (CuxS) were deposited at room temperature on glass substrates from solution containing copper (II) chloride, triethanolamine, and thiourea at appropriate pH (10-11). Two types of doping salts were used (AlCl3 & FeCl3) in four different weights (1, 1.5, 2, and 2.5) mg. The effect of introducing impurities and post-annealing was studied .The as-deposited films were found to
be amorphous, while the post annealed were polycrystalline. The changes in optical and electrical properties of doped films were also studied. The electrical conductivity was found to be highly dependent on annealing conditions, the resistivity of doped films was between (0.022-8.75) Ω cm. Optical band gaps of doped films determined from absorption spectra were found to have values within the range of (2.17-2.33) eV.