Rozana Aina Maulat Osman
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Preferred name
Rozana Aina Maulat Osman
Official Name
Rozana Aina, Maulat Osman
Alternative Name
Osman, R. A.M.
Osman, A. Rozana
Maulat Osman, Rozana Aina
Osman, Rozana A.M.
Osman, R.
Osman, R. A.Maulat
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Scopus Author ID
37261764900
Researcher ID
DXB-4277-2022

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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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Dielectric and microstructural properties of BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics

2017 , Fatin Adila Ismail , Rozana Aina Maulat Osman , Mohd Sobri Idris , Sanna Taking , Zul Azhar Zahid Jamal

BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics were investigated regarding their dielectric and microstructure properties via conventional solid state reaction method. The phase pure samples were obtained when heated at 1400°C for overnight. The effect of Er3+ doped into BaTiO3 on dielectric properties and microstructural properties was investigated for composition of BaTiO3 and Ba0.9925Er0.0075TiO3. The analysis was made by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Impedance Analyzer. The XRD patterns of BaTiO3 and Ba0.9925Er0.0075TiO3 are phase pure and identical with tetragonal perovskite structure with space group of P4mm. The lattice parameters and unit cell volume of BaTiO3 increased by doping with Erbium as the crystallite size decreased. Measurements of dielectric properties were carried out as a function of temperature up to 200°C at different frequencies. Ba0.9925Er0.0075TiO3 exhibit the high value of dielectric constant (ε=6179) at Curie temperature (TC) of 120°C. SEM analysis of BaTiO3 and Ba0.9925Er0.0075TiO3 ceramics showed that the grain sizes of BaTiO3 and Ba0.9925Er0.0075TiO3 were ranged from 3.3µm-7.8µm and 2.2µm-4.7µm respectively.

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Impedance and modulus spectroscopy of polycrystalline Ba0.9995La0.0005TiO3for multilayer ceramic capacitor

2021-07-21 , Tiong Yuan Tze , Rozana Aina Maulat Osman , Mohd Sobri Idris , Ku Noor Dhaniah Ku Muhsen , Nurul Izza Mohd Nor , Wahab Y.A. , Sagadevan S. , Sebastian T. , Arturo R.L.D.

Ba0.9995La0.0005TiO3 ceramics prepared via solid-state reaction route was found to be phase pure at the final sintering temperature of 1300°C for 16 hours. The dielectric constant was varied from 1900 to 2800 from 10 Hz to 100 kHz. Impedance spectroscopy is a powerful technique to study the complexities of ceramic materials such as homogeneity and inhomogeneity of materials that being process during production of most electronic materials. An electronic ceramic component can be visualized as a grain, grain boundary and electrode system. Impedance spectroscopy is being widely used to separate out contribution of the bulk and the grain boundary to the overall equivalent circuit models. Fixed frequency plots of dielectric constant versus temperature for Ba0.9995La0.0005TiO3 ceramics shows typical perovskite response with Curie temperature, Tc about 115 °C and fit with the equivalent circuit which contributed by bulk and grain boundary response.

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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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Indium (In) Effects to The Efficiency Performance of Ga1-XInxP/GaAs Based Solar Cell Using Silvaco Software Modelling & Simulation

2017-06-27 , Mohd Natashah Norizan , Suhaila Mohd Zahari , Ili Salwani Mohamad , Rozana Aina Maulat Osman , Shahimin M.M. , Sohiful Anuar Zainol Murad

Ga1-xInxP composition has been applied to the top cell of multi-junction GaInP/GaAs based solar cell and currently have achieving a conversion efficiency of more than 46%, however its capability is unclear. We performed an analysis using Silvaco simulation method to evaluate the effect of In and the substitution was made to the Ga1-xInxP for the range of x from 0 to 1. We found that the highest efficiency recorded was 17.66% when the composition of Indium was x=1. The efficiency has been increasing about 11.71% from x=0 to x=1 In content. As the composition of In raised, the value of efficiency and short circuit current density, Jsc also become higher (13.60 mA/cm2) by having a greater photon absorption in a wider band gap energy. In addition to that, Voc, Pmax, Vmax, Imax and fill factor was measured to be 2.15 V, 2.44 mW/cm2, 2.0 V, 1.22 mA/cm2 and 83.34 respectively. In conclusion, this study confirms that the existence of In in Ga1-xInxP improves the solar cell efficiency by gaining a higher energy gap and producing more electrons for best achievement in multilayer solar cell applications.

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The effect of cation ordering on the structure, electrical and electronic properties of cubic spinel LiNi₀.₅Mn₁.₅O₄

2025-01 , Edi Yasa Ardiansyah , Mohd Sobri Idris , Rozana Aina Maulat Osman , Fahmi Fahmi

In this paper, we present the investigation of the impact of cation ordering on the structural, electrical, and electronic properties of a cubic spinel LiNi₀.₅Mn₁.₅O₄. Rietveld refinement using X-ray diffraction (XRD) data reveals that LiNi₀.₅Mn₁.₅O₄ annealed at 700 °C adopts a well-ordered atomic arrangement in cubic spinel (SG = P4332). Then, it is transformed to a disordered cubic spinel (SG = Fd-3m) at higher temperatures (> 800 °C). Impedance spectroscopy is employed to evaluate the dielectric and electrical properties in the temperature range of 0 to 25oC within the frequency range between 10 Hz and 100 kHz. The Cole-Cole plot indicates that grain boundaries contribute significantly to electrical conductivity and that bulk resistance decreases with increasing temperature. The AC conductivity analysis shows that the electrical conductivity of well-ordered and disordered cubic spinel LiNi₀.₅Mn₁.₅O₄ exhibits thermal activation and obeys Jonscher's universal power law. Furthermore, the electronic properties of cubic spinel LiNi₀.₅Mn₁.₅O₄ with the space groups of Fd-3m and P4332 are investigated using the density functional theory (DFT) plane-wave method. The electronic analysis of the cubic spinel LiNi₀.₅Mn₁.₅O₄ (SG = Fd-3m) indicates stronger bonding between oxygen and transition metal elements compared to the LiNi₀.₅Mn₁.₅O₄ (SG = P4332) structure. Therefore, LiNi₀.₅Mn₁.₅O₄ with the Fd-3m space group exhibits high structural stability, making it a favourable cathode material for high-voltage rechargeable lithium-ion batteries.

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Dielectric and structural analysis of hexagonal and tetragonal phase BaTiO3

2020-01-08 , Yusoff, Nurul Huda , Rozana Aina Maulat Osman , Mohd Sobri Idris , Muhsen, Ku Noor Dhaniah Ku , Nurul Izza Mohd Nor

Barium titanate (BaTiO3) has been synthesized using conventional solid state reaction method at sintering temperatures of 1150°C and 1400°C. A single phase tetragonal perovkite BaTiO3 was observed at 1150°C and changed to hexagonal phase at 1400a°C. The result was confimed by using X-ray diffraction analysis. Hexagonal BaTiO3 exhibits almost linear dielectric constant value between 60 to 120, however the tetragonal phase shows a phase transition from tetragonal to cubic at 120a°C. The tetragonal phase BaTiO3 has the highest dielectric constant 6000 at Tc and 4000 at room temperature.

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Junction engineering in two-stepped recessed SiGe MOSFETs for high performance application

2020-01-08 , Wahab Y.A. , Soin N. , Naseer M.N. , Hussin H. , Rozana Aina Maulat Osman , Johan M.R. , Hamizi N.A. , Pivehzhani O.A. , Chowdhury Z.Z. , Sagadevan S. , Thennarasan Sabapathy

SiGe being one of the most diverse, emerging and richest material for MOSFETs is alluring the scientist due to its unique characteristics like high performance, high surface channel mobility and low threshold voltage as compare to that of silicon MOSFETs. In spite of so much cruciality, the performance of SiGe MOSFETs is being controlled by several factors like resistance and junction depth. These factors urged scientists to not relieve on the traditional methods of junction meteorology to utilize the actual potential and high performance of SiGe MOSFETs in terms of their application. Hence, a paradigm shift in junction engineering is being observed during last few years and discussed. The main focus of this paper is to highlight junction metrologies (ion implantation and annealing) that were tested on SiGe MOSFETs and to propose the most efficient and sustainable technique of junction engineering for high performance applications.

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Effect of Sn Doping on the Curie Temperature, Structural, Dielectric and Piezoelectric Properties of Ba0.8Sr0.2Ti1−xSnxO3 Ceramics

2023-11-01 , Nasir N.N. , Rozana Aina Maulat Osman , Mohd Sobri Idris , Muhsen K.N.D.K. , Prabakaran A/L Poopalan , Nur Izzati Muhammad Nadzri , Jumali M.H.H. , Jamil N.H.B.

Ba0.8Sr0.2Ti1−xSnxO3 material with varying Sn concentrations (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10) was synthesized using the conventional solid-state reaction method. X-ray diffraction (XRD) analysis reveals that as the Sn concentration increases from x = 0 to x = 0.10, the Ba0.8Sr0.2Ti1−xSnxO3 undergoes a structural phase change from tetragonal to cubic. Dielectric analysis of Ba0.8Sr0.2Ti1−xSnxO3 shows a significant drop in Tc, from 65 to 5°C, caused by the replacement of Sn4+ ions with larger ionic radii compared to Ti4+ ions at the B-sites. The composition with x = 0 exhibits the largest dielectric constant due to its enormous spontaneous dipole moments. Conversely, the substitution of Sn in Ba0.8Sr0.2Ti1−xSnxO3 reveals a decrease in the dielectric constant at the B-site structure of perovskite, resulting in a reduced tolerance factor and a decrease in the tetragonality of the sample. However, the pinching effect significantly enhances the dielectric constant of the sample with x = 0.10. Grain size measurements for x = 0 demonstrate a well-distributed grain structure. Additionally, the undoped sample exhibits a higher piezoelectric constant than the Ba0.8Sr0.2Ti1−xSnxO3 samples. According to the piezoelectric constant data, the composition with a tetragonal structure appears to have a greater piezoelectric constant than the cubic structure.

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Ga 2 O 3 thin films by sol-gel method its optical properties

2020-01-08 , Cheah L. , Rozana Aina Maulat Osman , Prabakaran A/L Poopalan

Gallium (III) oxide Ga2O3 is emerging in the field of wide bandgap semiconductor for various applications such as solar-blind photodetectors et al. because of its wide bandgap. For this reason, the optical properties of Ga2O3 by sol-gel method are analyzed. Ga2O3 thin films are prepared by spin coating method. The annealing temperature to make α-Ga2O3 is in the range of 450°C-550°C, where after 550°C, β-Ga2O3 is obtained as reported in reviewed works. Therefore, annealing temperatures of samples are set at 500°C, 700°C and 900°C. X-ray diffraction is performed to characterize the structure of the sample. The optical bandgap of Ga2O3 is calculated based on the transmittance value measured from UV-Visible spectrophotometer, which range from 4.8eV to 5.0eV.

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