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Effect of Reaction Temperature and Time on the Structural Properties of Cu(In,Ga)Se_2 Thin Films Deposited by Sequential Elemental Layer Technique

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Journal of Materials Science & Technology 2007年第4期23卷 499-503页

作者： Saira RIAZ shahzad naseem Centre for Solid State Physics University of the Punjab QACLahore-54590Pakistan

Thin films of copper indium gallium selenide Cu（In,Ga）Se2 （CIGS） were prepared by sequential elemental layer deposition in vacuum at room temperature. The as-deposited films were heated in vacuum for compound formation, and were studied at temperature as high as 1250℃ for the first time. These films were concurrently studied for their structural properties by X-ray diffraction （XRD） technique. The XRD analyses include phase transition studies, grain size variation and microstrain measurements with the reaction temperature and *** has been observed that there are three distinct regions of variation in all these parameters. These regions belong to three temperature regimes：〈450℃, 450-950℃, and 〉950℃. It is also seen that the compound formation starts at 250℃, with ternary phases appearing at 350℃ or above. Whereas, there is another phase shift at 950℃ without any preference to the quaternary compound.

关键词： Cu(In,Ga)Se2 (CIGS) X-ray Diffraction Thin films Structural analysis

Surface Passivation of Ti/4H-SiC Schottky Barrier Diode

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Communications in Theoretical Physics 2012年第10期58卷 577-582页

作者： Muhammad Khalid Saira Riaz shahzad naseem Microelectronics Division/Centre of Excellence in Solid State Physics School of Physical SciencesUniversity of the Punjab

Surface properties of SiC power devices mostly depend on the passivation layer(PL).This layer has direct influence on electrical characteristics of devices.2D numerical simulation of forward and reverse characteristics with and without different(PLs)(SiO2,HfO2 and Si3N4) has been *** results show that the breakdown voltage increases with increasing PL thickness,and there is a lesser significant effect on forward *** maximum breakdown voltage with and without SiO2 PL is 1240 V and 276 V,***2 PL has compatibility with SiC surface providing high breakdown voltage,6 and 8% higher than that of HfO2 and Si3N4 *** leakage current is observed which then further decreases on reducing the thickness of ***,variation of forward current with dielectric constant and thickness of PLs was ***,it is suggested that matches of our results with published experimental results indicate that the Sentaurus TCAD simulator is a predictive tool for the SiC Schottky barrier diode simulation.

关键词： Passivation breakdown voltage leakage current electric field on-resistance

Evaporated Thin Films of CdS and CdTe: Optimization for Photovoltaic Applications

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Journal of Materials Science & Technology 1996年第2期12卷 89-94页

作者： shahzad naseem Dilawaiz Nazir Riffat Mumtaz Khadim Hussain Centre for Solid State Physics University of the PunjabQuaid-e-Azam CampusLahore-54590Pakistan

Thin films of cadmium sulphide and cadmium telluride have been prepared by thermal evaporation under various conditions of deposition. These films have been characterized optically. electrically and for structure determination. The results of these characterizations along with the initial results of all thin film CdS/CdTe solar cells are presented in this paper

关键词： Evaporated Thin Films of CdS and CdTe Thin Optimization for Photovoltaic Applications CdS

Structural and Magnetic Properties of Chemically Synthesized Pd-Modified NiFe2O4 Nanoparticles

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Chinese Journal of Chemical Physics 2016年第2期29卷 245-248,I0002页

作者： Shahid Aatiq Shahid M. Ramay Asif Mahmood SairaRiaza shahzad naseem 巴基斯坦旁遮普邦大学固体物理卓越中心拉合尔100190 沙特阿拉伯沙特国王大学理学院物理与天文学系利雅得11421 沙特阿拉伯沙特国王大学工程学院化学工程系利雅得11421

Magnetic nanoparticles of NiFe2O4-Pd composites have been synthesized using a simple, low cost, sol-gel auto-combustion method. As-prepared samples were sintered at 800℃ for 6 h in order to develop the crystalline phase. X-ray diffraction confirmed the spinel structure of the ferrite samples. Structural morphology and size of the nanoparticles were evaluated using a field emission scanning electron microscope. Magnetic hysteresis loops were obtained at 300 and 100 K using a physical properties measurement system. The value of saturation magnetization was observed to decrease at the temperatures with the increase of Pd contents up to 5% but then a sudden rise in saturation magnetization was observed for the addition of 10% Pd in NiFe2O4.

关键词： Magnetic nanoparticles Sol-gel auto-combustion Low temperature magneticproperty

Origin of Ferromagnetism in Al and Ni Co-doped ZnO Based DMS Materials

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Chinese Physics Letters 2012年第10期29卷 155-157页

作者： Murtaza Saleem Saadat A.Siddiqi Shahid M.Ramay Shahid Atiq shahzad naseem Centre for Solid State Physics University of the PunjabQuaid-e-Azam CampusLahore 54590Pakistan 2Interdisciplinary Research Centre in Biomedical MaterialsCOMSATS Institute of Information TechnologyDefence RoadOff Raiwind RoadLahorePakistan 3Department of Chemical EngineeringCollege of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia

Zn0.95Ni0.05O and Zn0.90Ni0.05Al0.05O compositions of nanocrystallites are synthesised using the well recognised auto-combustion *** x-ray diffraction patterns demonstrate the phase pure characteristic wurtzite-type crystal structure with space group P63mc in both the *** elemental incorporation of Ni and Al contents into the ZnO structure is confirmed by energy dispersive x-ray *** micrographs of scanning electron microscopy show an approximate ordered *** electrical resistivity is observed to decrease with the rising temperature,depicting the characteristic semiconductor behaviour of the *** lower values of resistivity and ferromagnetic interactions in the Al-doped sample correspond to an increase of carrier's *** is observed that the carrier mediated mechanism is mainly responsible for ferromagnetism in ZnO-based diluted magnetic semiconductors.

关键词： resistivity diluted Origin

Structural and dielectric properties of doped ferrite nanomaterials suitable for microwave and biomedical applications

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Progress in Natural Science:Materials International 2015年第5期25卷 419-424页

作者： Imran Sadiq shahzad naseem Muhammad Naeem Ashiq M.A.Khan Shanawer Niaz M.U.Rana Centre of Excellence in Solid State Physics University of the Punjab Institute of Chemical Sciences Bahauddin Zakariya University Department of Physics BUITEMS 4. Department of Physics University of Sargodha

The sol-gel auto-combustion method was adopted to synthesize nanomaterials of single-phase X-type hexagonal ferrites with the composition of Sr;Gd;Ni;Fe;Cd;O;（x=0.00,0.02,0.04,0.06,0.08,0.10 and y = 0,0.1,0.2,0.3,0.4,0.5）.The structural properties were carried out by XRD analysis and the lattice parameters show variation with the doping of *** average particle size measured by TEM was in the range of 8-10 nm which is beneficial in obtaining suitable signal-to-noise ratio in recording media and biomedical *** room temperature resistivity enhanced with the increase of the dopant *** increase in resistivity indicates that the synthesized materials can be considered good for the formation of the multilayer chip inductors（MLCIs） as well as for the reduction of eddy current *** dielectric constant decreased with the increase in the frequency which is the general reported trend of the hexagonal ferrites and can be explained on the basis of Koop’s theory and Maxwell-Wagner *** abnormal dielectric behavior indicates the formation of small polarons in the *** maximum value of tangent loss at low frequencies reflects the application of these materials in medium frequency devices（MF）.

关键词： Sol–gel Nanocrystalline materials Thermal properties Electrical properties Dielectric properties

Auger Depth Profiling of Carbonized SiC/Si Samples

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Journal of Materials Science & Technology 1997年第6期13卷 499-502页

作者： shahzad naseem and Shazia Yasin(Centre for Solid State Pliysics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan) Centre for Solid State Physics University of the Punjab Quaid-e-Azam Campus Lahore-54590 Pakistan Microelectronics Research Centre Cavendish Lab. University of Cambridge Madingley Road Cambridge CB3 OHE United Kingdom

Silicon carbide (SiC) has been prepared by passing natural gas over (100) oriented hot Si substrate at different temperatures in the range 930~1000℃. Reaction times of 60 and 90 min are *** profile, using Auger Electron Spectroscopy, shows the formation of SiC under a thin coating of carbon for the samples prepared at 930 and 950℃. Annealing, at 1050℃ for 12 h,results in a more pronounced formation of SiC. It is found that at the temperature of 1000℃and reaction times of 60 and 90 min, a hard diamond-like coating is formed.

关键词： SiC Auger Depth Profiling of Carbonized SiC/Si Samples

Preparation and characterization of doubly substituted microwave absorbing material by sol-gel technique for super high frequency applications

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Progress in Natural Science:Materials International 2018年第4期28卷 478-482页

作者： Imran Sadiq shahzad naseem Saira Riaz S.Sajjad Hussain Muhammad Naeem Ashiq Mazhar Rana Centre of Excellence in Solid State Physics University of the Punjab Institute of Chemical sciences Bahauddin Zakariya University

Rare earth Dy;and divalent Mn;elements substituting W-type hexagonal ferrites Ba;Dy;Zn;Fe;Mn;O;（x=0,0.02,0.06,0.1 and y=0,0.1,0.3,0.5）were prepared by sol-gel *** thermo-gravimetric analysis（TGA）and differential scanning calorimetry（DSC）was carried out to find the temperature at which single phase can be *** patterns indicate the presence of the single phase for all the synthesized samples with the absence of any extra peak due to unreacted material and secondary *** occurrence of absorption bands at low wave numbers(563 and 446 cm;),can be assigned to the stretching vibration of metal and oxygen ions in FTIR spectra,which also confirms the single hexagonal phase for prepared *** grains are of platelet like structure,which enhances the microwave absorption properties of hexagonal *** synthesized material exhibits the minimum reflection loss of-20.9 dB at 11.8 GHz frequency,which reflects the applications of this material in super high frequency *** microwave conductivity of the material increases with frequency.

关键词： Sol-Gel synthesis XRD Microwave absorption properties Microwave conductivity

PREPARATION OF THERMALLY EVAPORATED CdTe THIN FILMS

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Chinese Physics Letters 1990年第11期7卷 510-513页

作者： shahzad naseem Naseer-ud-Din Khadim Hussain Centre for Solid State Physics University of the PunjabQuaidCampusLahorePakistan

Thin films of cadmium telluride were prepared by evaporating cadmium telluride powder in a vacuum of less than 10^(-4) *** substrate temperature was varied systematically from room temperature to 300℃.The results of optical and structural characterizations have revealed that the films posses a high value of absorption coefficient with a bandgap value m the range 1.475-1.769eV,and that the films are of cubic structure with a preferred orientation along(111)*** probe measurements have shown that resistivity of these films is affected by the change in substrate temperature,with the lowest value(12.6 Ω·cm)being at 200℃.

关键词： films value cadmium