Zul Azhar Zahid Jamal
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Preferred name
Zul Azhar Zahid Jamal
Official Name
Zul Azhar, Zahid Jamal
Alternative Name
Jamal, Z. A. Z.
Jamal, Zul Azhar Zahid
Jamal, Z. A. Zahid
Jamal, ZA
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Scopus Author ID
18935174100
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FCT-5153-2022

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Electrical properties of Sn doped SrTiO₃

2020-01 , Muhammad Haniff Fisoldin , Mohd Sobri Idris , Rozana Aina Maulat Osman , Ku Noor Dhaniah Ku Muhsen , Zul Azhar Zahid Jamal

The crystal structure and electrical properties of SrTiO₃ with addition of 50 mol% SnO2 was studied. Samples were prepared using conventional solid-state reaction route. The results indicate that Sn doped SrTiO₃ was single phase with cubic phase and space group Pm-3m after final sintering temparture at 1400°C. Two semicircular arcs clearly observed in Z" versus Z' plots for SrTi0.5Sn0.5O3 semicircles associated with bulk relaxation processes and grain boundary effect. The heterogeneity of sample was observed form Z' and M" spectroscopic plot. The highest dielectric constant is observed at much higher temperature which nearly 2000 at low frequency measurement.

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Structural and electrical properties of Barium Titanate (BaTiO3) and Neodymium doped BaTiO3 (Ba0.995Nd0.005TiO3)

2017 , Tuan Amirah Tuan Sulong , Rozana Aina Maulat Osman , Mohd Sobri Idris , Zul Azhar Zahid Jamal

Barium titanate (BaTiO3) and Neodymium (Nd) doped BaTiO3 with composition Ba0.995Nd0.005TiO3 were prepared using conventional solid state reaction method to study the dielectric properties of materials. Pure phase samples were found at final heating temperature of 1400°C for overnight. X-ray diffraction analysis reveals the changes in the lattice parameter and unit cell volume of the pure perovskite tetragonal structure with space group (P4mm). Electrical analysis is carried out to investigate the dielectric properties, conductivity behaviour and dielectric loss of BaTiO3 and Ba0.995Nd0.005TiO3. Ba0.995Nd0.005TiO3 have a broaden dielectric peaks with high permittivity of 8000 and reasonably low loss tan δ which is about 0.004 (1 kHz).

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Design and fabrication of quantum dot single electron transistor structure using e-beam nanolithography

2011-07 , Uda Hashim , S. Madnasri , Zul Azhar Zahid Jamal

Quantum dot single electron transistor (QD SET) is fabricated using e-beam nanolithography (EBL) and is continued with the combination process of pattern dependent oxidation (PADOX) and high density plasma etching. EBL was used to pattern the whole masks of SET fabrication which consist of mask for doped area separator and the rest are for the formation of: source-quantum dot-drain, poly-Si gate, point contact and metal pad respectively. All of these masks were designed using offline GDSII Editor Software and later been exposed by EBL integrated using the scanning electron microscopy (SEM). In this paper, the whole designs of SET masks which are successively patterned are demonstrated and their nanostructures characterizations using SEM and atomic force microscopy (AFM) are reported. We found that the shape and dimension biases of schematic and SEM images of masks were caused by proximity effect. Therefore, while designing the SET masks, proximity effect, used resist and EBL equipment resolution were considered.

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Mineralogical characterizations of Langkawi ilmenite ore for carbothermal reduction

2022-01-01 , Mohammed A.I. , Nur Farhana Diyana Mohd Yunos , Muhammad Asri Idris , Zul Azhar Zahid Jamal , Nur Farhana Hayazi , Nomura T.

The mineralogical characterizations of Langkawi’s ilmenite were investigated using XRD, XRF and SEM/EDS for morphological analysis. The minerals mainly consisted the phases of FeTiO3, Fe3O4 and TiO2 and Rietveld refinement indicated that the ore contained 35.85% of TiO2 and 26.52% of Fe3O4. The amount of the elements calculated form the quantitative and XRF analysis are reliable and in acceptable ranges. The morphology of the ore showed that the ore is formed mainly in sub-rounded grains with titanium and iron as main elements. The ore was categorized as a low-grade ore, but it can be upgraded for TiO2 production using carbothermal reduction reactions, where the results of XRD, XRF, SEM showed extractable amount of TiO2 more than 32wt%.

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Physical, electrical and optical characterizations of Ba0.5Sr0.5TiO3 (BST) thin films

2020-01-08 , Bakar Nurhanani Abu , Adnan Johari , Rozana Aina Maulat Osman , Zul Azhar Zahid Jamal , Muhammad Asri Idris , Wan Mohd Faizal Wan Nik , Man Bahari

Single layer Barium Strontium Titanate (BaxSr1-xTiO3) thin films were deposited on P type Silicon (Si) and thin Silicon Dioxide (SiO2) layer grown on Silicon (Si) substrate (1.5 cm x 1.5 cm) using spin coating technique were investigated in this work. The thin films were crystallized by annealing at 950 °C for 4 hours. Physical characterization was performed using XRD. Electrical and optical characterizations were aided by depositing Aluminum (Al) using Physical Vapor Deposition (PVD) on the thin films as electrode metal. I-V profile was obtained using Semiconductor Parametric Analyzer (SPA). A high impedance multimeter, light meter and a variable light source were introduced for optical characterizations including optical sensitivity, current density and I-V profile under variable light intensity from 0 to 900 Lux. Results show BST has diode like characteristics. The results which were compared with those from commercial solar cells and light sensors indicated that the BST thin films have potential as solar power generator and sensor.

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Nano-silver microcavity enhanced UV GaN light emitter

2009 , Ahmed, Naser Mahmoud , Zaliman Sauli , Uda Hashim , Zul Azhar Zahid Jamal

We report results of measurements that help to clarify the role of silver in the reflection of UV emission light from GaN. A GaN as an active layer was sandwiched between two silver metal reflectors. GaN layer on sapphire showed a photoluminescence (PL) peak around 364 nm and its full width half maximum was about 6.7 nm. Two types of microcavity, were fabricated: half-cavity GaN/sapphire/silver and full-cavity silver/ GaN/sapphire/silver. Photoluminescence measurements showed a two-fold intensity enhancement in half-cavity back mirror. In the full cavity samples, the amplitude of the photoluminescence is enhanced ten times when we used 50 nm silver as a front mirror. A tremendous more than 16-fold enhancement is obtained when silver mirror of 25 nm was used as a front mirror. The increase in the photoluminescence intensity is explained in terms of competition between increasing absorption in the cavity, silver surface plasmon coupling and increasing optical field-enhancement due to resonator.

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Synthesis and process evaluation of calcium phosphate coatings depositions on pure magnesium via simple chemical conversion method

2018-12 , Mohd Amin Farhan Zaludin , Zul Azhar Zahid Jamal , Mohd Nazree Derman , Azmi Rahmat , Mohd Zaheruddin Kasmuin

Simple chemical conversion has been employed in order to coat calcium phosphates (CaP) on magnesium (Mg) substrate. The Mg substrates were coated in a primary phosphating bath before secondary treated with an alkaline solution of sodium hydroxide, NaOH. In this paper, the fabrication process of the coatings via simple chemical conversion method were discussed and evaluated in terms of electrochemical, phase analysis, and microstructural aspects. XRD diffractogram confirmed that the primary coating composed of dicalcium phosphate dehydrates (DCPD) and after the secondary treatment, the DCPD transformed into more stable hydroxyapatite, HA. The microstructural observations show that the coating is composed of flower-like shape crystallites. Besides, the potential-time curves of both primary and secondary coated samples suggests that the minimum deposition time for better coverage of the coatings is 30 minutes.

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Mineralogical characterizations of Langkawi Ilmenite ore for carbothermal reduction

2022-01 , A. I. Mohammed , Nur Farhana Diyana Mohd Yunos , Muhammad Asri Idris , Zul Azhar Zahid Jamal , Nur Farhana Hayazi , T. Nomura

The mineralogical characterizations of Langkawi’s ilmenite were investigated using XRD, XRF and SEM/EDS for morphological analysis. The minerals mainly consist of the phases of FeTiO3, Fe3O4 and TiO2 by Rietveld refinement, which indicated that the ore contains 35.85% of TiO2 and 26.52% of Fe3O4. The amount of the elements calculated from the quantitative and XRF analysis are reliable and in acceptable ranges. The morphology of the ore shows that the ore is formed mainly in sub-rounded grains with titanium and iron as the main elements. The ore is categorized as a low-grade ore, but it can be upgraded for TiO2 production using carbothermal reduction reactions, where the results of XRD, XRF, SEM showed an extractable amount of TiO2 more than 32wt%.

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Frequency dependent electrical properties of ferroelectric Ba₀.₈Sr₀.₂TiO₃ thin film

1970 , Ala’eddin A. SAIF , Zul Azhar Zahid Jamal , Zaliman Sauli , Prabakaran A/L Poopalan

The frequency dependent electrical parameters, such as impedance, electric modulus, dielectric constant and AC conductivity for ferroelectric Baâ‚€.₈Srâ‚€.â‚‚TiO₃ thin film have been investigated within the range of 1 Hz and 106 Hz at room temperature. Z* plane shows two regions corresponding to the bulk mechanism and the distribution of the grain boundaries-electrodes process. M" versus frequency plot reveals a relaxation peak, which is not observed in the ε″ plot and it has been found that this peak is a non-Debye-type. The frequency dependent conductivity plot shows three regions of conduction processes, i. e., a low-frequency region due to DC conduction, a mid-frequency region due to translational hopping motions and a high-frequency region due to localized hopping and/or reorientational motion.http://dx.doi.org/10.5755/j01.ms.17.2.490

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Computational fluid dynamic (CFD) of air conditioning system for human thermal comfort analysis: A simulation study

2019-04-08 , Ali A.M. , Shazmin Aniza Abdul Shukor , Rahim N.A. , Zuradzman Mohamad Razlan , Zul Azhar Zahid Jamal , Kohlhof K.

Human thermal comfort is very important especially in an indoor environment because it may effect human's health and welfare. Air conditioning (AC) system has become a necessary tool for indoors to maintain human comfort. This is especially applied to places with high strength of solar radiation, high relative humidity, high air temperature, and low air speed areas which are considered the most critical climate effect for indoors such as in Thailand, Malaysia, and Singapore. However, the current mechanism of the AC system allows the user to set it into maximum cooling, i.e. at the lowest temperature with highest fan speed. This setting does not necessarily create a thermally comfortable environment inside the room, but could contribute towards negative impact to human. Thus, there is a need to study the possibility of integrating the element of thermal comfort with the AC system. This project will concentrate on a case study of the effect of AC towards human thermal comfort in an indoor environment by using computational fluid dynamic (CFD) flow simulation. It adapts an enhanced Predicted Mean Vote (PMV)-based algorithm in creating the thermal comfort environment. The simulation uses SOLIDWORKS software and concentrates on a small sized room with one person doing sedentary work. The flow simulation is done on four conditions-maximum cooling setting and other three that is based on the enhanced PMV algorithm, which were then analyzed and compared. Based on the results, it is shown that the enhanced PMV-based algorithm could provide a thermally comfortable environment compared to the maximum cooling setting.

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