Safizan Shaari
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Preferred name
Safizan Shaari
Official Name
Safizan, Shaari
Alternative Name
Shaari, Safizan
Shaari, S.
Main Affiliation
Scopus Author ID
55807708700
Researcher ID
AAR-5562-2021

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  • Publication
    Silicon Self-Switching Diode (SSD) as a Full-Wave Bridge Rectifier in 5G networks frequencies
    ( 2022)
    Tan Yi Liang
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Arun Kumar Singh
    ;
    Mohd Khairuddin Md Arshad
    The rapid growth of wireless technology has improved the network’s technology from 4G to 5G, with sub-6 GHz being the centre of attention as the primary communication spectrum band. To effectively benefit this exclusive network, the improvement in the mm-wave detection of this range is crucial. In this work, a silicon self-switching device (SSD) based full-wave bridge rectifier was proposed as a candidate for a usable RF-DC converter in this frequency range. SSD has a similar operation to a conventional pn junction diode, but with advantages in fabrication simplicity where it does not require doping and junctions. The optimized structure of the SSD was cascaded and arranged to create a functional full-wave bridge rectifier with a quadratic relationship between the input voltage and outputs current. AC transient analysis and theoretical calculation performed on the full-wave rectifier shows an estimated cut-off frequency at ~12 GHz, with calculated responsivity and noise equivalent power of 1956.72 V/W and 2.3753 pW/Hz1/2, respectively. These results show the capability of silicon SSD to function as a full-wave bridge rectifier and is a potential candidate for RF-DC conversion in the targeted 5G frequency band and can be exploited for future energy harvesting application.
  • Publication
    Hybrid statistical and numerical analysis in structural optimization of silicon-based RF detector in 5G network
    ( 2022-01-21)
    Tan Yi Liang
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Arun Kumar Singh
    ;
    Sharizal Ahmad Sobri
    In this study, a hybrid statistical analysis (Taguchi method supported by analysis of variance (ANOVA) and regression analysis) and numerical analysis (utilizing a Silvaco device simulator) was implemented to optimize the structural parameters of silicon-on-insulator (SOI)-based self-switching diodes (SSDs) to achieve a high responsivity value as a radio frequency (RF) detector. Statistical calculation was applied to study the relationship between the control factors and the output performance of an RF detector in terms of the peak curvature coefficient value and its corresponding bias voltage. Subsequently, a series of numerical simulations were performed based on Taguchi’s experimental design. The optimization results indicated an optimized curvature coefficient and voltage peak of 26.4260 V−1 and 0.05 V, respectively. The alternating current transient analysis from 3 to 10 GHz showed the highest mean current at 5 GHz and a cut-off frequency of approximately 6.50 GHz, indicating a prominent ability to function as an RF detector at 5G related frequencies.
  • Publication
    A review of visible-to-UV photon upconversion systems based on triplet–triplet annihilation photon upconversion
    ( 2022-12)
    Kelvin Voon Yan Jie
    ;
    Mohd Fairus Ahmad
    ;
    Muhammad Mahyiddin Ramli
    ;
    Safizan Shaari
    ;
    Arif Mawardi Ismail
    ;
    Yusran Sulaiman
    Due to the tunable spectrum range and potential application under non-coherent solar irradiation, triplet-triplet annihilation based molecular photon upconversion (TTA-UC) systems represent a compelling study field for a variety of photonic implementations. There were studies on the incorporation of TTA-UC technology with photovoltaic technology, which made it possible to further improve the energy harvest performance through the utilisation of the wasted spectrum. However, many TTA-UC studies are limited to energy upconversion within the visible spectrum range. For photovoltaic cells with a higher band gap, which harvest the higher energy spectrum (UV region), an efficient Vis-to-UV upconversion is preferred. The Vis-to-UV TTA-UC system was first introduced in 2006. Recently, more studies were conducted to discover the Vis-to-UV upconversion system with high quantum efficiency and low excitation intensity such as the nanocrystal sensitizerbased system and the thermally activated delayed fluorescence sensitizer-based system. Recent studies in the solvent system of Vis-to-UV upconversion system had demonstrated the dependence of the couple photostability on the solvent and extended the solvent selection to inorganic solvent. In this review, we are reviewing the research background of the Vis-to-UV TTA-UC system and discussing the current challenges and potential developments in this research area.
  • Publication
    Fabrication of Strontium Titanate thin film with pre-crystallized layer via sol-gel spin coating method
    ( 2022-12)
    Kelvin Voon Yan Jie
    ;
    Mohd Fairus Ahmad
    ;
    Muhammad Mahyiddin Ramli
    ;
    Safizan Shaari
    ;
    Arif Mawardi Ismail
    ;
    Yusran Sulaiman
    The technique of pre-crystallized layer is introduced in the strontium titanate (STO) thin film fabrication to improve the coating thickness and the crystallinity. The STO thin films were fabricated on glass substrates via the spin coating method with STO precursor solution that was synthesized through the sol-gel process. The characteristics of the thin films were analyzed through X-ray diffraction (XRD) analysis, profilometry, UV-Vis spectra analysis and scanning electron microscopy (SEM) analysis. In the present study, the samples of 20 layers and 25 layers (deposited on the pre-crystallized layer) exhibited better crystallinity as compared with the samples of 5 layers, 10 layers and 15 layers (without the pre-crystallized layer). The samples of 25 layers exhibited the highest film thickness (224 nm), highest absorbance intensity and the highest XRD peak intensity at 32, 40, 47 and 58°, which represent the planes (110), (111), (200) and (210), respectively. The pre-crystallized layer served as the mechanical support for further layer deposition.
  • Publication
    Modification of photoanode surface structure via image analysis on organic polymer material based for dye-sensitized solar cell (DSSC) applications
    ( 2021-12)
    N. Rosli
    ;
    Norhayati Sabani
    ;
    MF Ahmad
    ;
    Mohd. Azarulsani Md. Azidin
    ;
    Nurjuliana Juhari
    ;
    NF Zakaria
    ;
    Mohd Natashah Norizan
    ;
    Safizan Shaari
    In this study, the experiment on the modification of the photoanode with organic polymer material as copolymer template for dye-sensitized solar cell (DSSC) applications has been conducted. The two organic copolymer templates are polystyrene sphere (PS) and poly[2- methoxy-5(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). The modification photoanodes were made using Dr. Blade’s method. These organic copolymer templates were added to improve the surface of the mesoporous titanium dioxide (TiO₂) layer, which is used as the main component in DSSC photoanode. The unmodified TiO₂ photoanode has poor aggregation and porosity of TiO₂. The addition of either MEH-PPV or PS sphere to the photoanode layer was found to affect the surface of mesoporous TiO₂ in terms of porosity, particle size distribution and shape. The analysis of the TiO2 modification was conducted using an image analysis processing method via a 2D scanning electron microscope (SEM) image. The image analysis processing method used was the ImageJ program. The DSSC of modified photoanode is fabricated using metal complex dye, Ruthenium (N719) dye. The data collected from the ImageJ program showed that by adding organic copolymer templates into TiO₂, the porosity of TiO₂ decreased from 45 % to 42 %. From the photovoltaic analysis obtained, the J-V characteristic is recorded with the photoanode of TiO₂ mixed with 1.00 wt% MEH-PPV gave the highest efficiency, which is 0.01 % with the following parameters – Voc = 0.43 V, Jsc = 0.17 mA/cm2 and FF = 0.20. Meanwhile, the photoanode of TiO₂ mixed with 0.50 wt% PS sphere gave the highest efficiency which is 0.08 % with the following parameters – Voc = 0.39 V, Jsc = 0.86 mA/cm2 and FF = 0.25.
  • Publication
    Optimization of MEH-PPV based single and double-layer TOLED structure by numerical simulation
    ( 2021-12)
    T. Kersenan
    ;
    Nor Farhani Zakaria
    ;
    Safizan Shaari
    ;
    Norhayati Sabani
    ;
    Nurjuliana Juhari
    ;
    Meor Ahmad Faris bin Meor Ahmad Tajudin
    ;
    A.F.A Rahim
    In this work, we simulated and characterized Poly [2-methoxy-5-(2’-ethylhexyloxy)-1, 4-phenylene vinylene] (MEH-PPV) based single and double-layer TOLED by using Silvaco ATLAS device simulator to achieve prominent values of electrical and optical properties of the device. MEH-PPV were used as the emitting layer (EML) in the single-layer, while addition of Poly [(3,4-ethylene dioxythiophene)-poly(styrene sulfonate)] (PEDOT-PSS) as the electron transport layer (ETL) were conducted in double-layer TOLED simulation. The EML and ETL thickness in both structures were varied between 10 – 150 nm, respectively, to observe and understand the underlying physics of the relation in the layer thickness to the electrical and optical characteristics. Furthermore, variation of the EML/ETL thickness ratio from 1:1 to 5:1 (with thickness in between 10 to 50 nm) had also been conducted. From this work, it is understood that the thickness of the EML layer plays the most important role in TOLED, and by balancing the carrier injections and recombination rate in appropriate EML/ETL thickness ratio, the electrical and optical properties can be improved. By optimizing the EML/ETL thickness and thickness ratio, an optimal forward current of 1.41 mA and luminescent power of 1.93e-18 W/μm has been achieved with both MEH-PPV and PEDOT-PSS layer thickness of 10 nm (1:1 ratio), respectively. The results from this work will assist the improvement of TOLED device to be implemented widely in low power and transparent electronic appliances.
  • Publication
    Numerical simulation and characterization of silicon based OR logic gate operation using self-switching device
    ( 2021-12)
    Y.X. Goh
    ;
    Nor Farhani Zakaria
    ;
    Y. L. Tan
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    A. K. Singh
    Logic gates are the main components inside the integrated circuit used for almost every technological application. Nowadays, in order to enhance the performance of the smart device, while targeting in cut down of the fabrication cost and achieve low power consumption, lithography-based VLSI design technology on silicon are still being widely applied. Hence, an OR gate structure, a silicon based self-switching device (SSD) is introduced and investigated in this project. Such device is believed capable to act as an alternative for a low-powered logic gate application, suitable for CMOS devices. The SSD has an advantage in term of simplicity in fabrication process with a very low threshold voltage. Since SSD characteristics is similar to a conventional diode characteristic, the gate is designed in ATLAS Silvaco device simulator based on a diode logic to perform OR logic function after a validation of the physical and materials parameters. The electrical characterization and structural analysis were also done to observe the electrical performance and physical condition in the device. The simulated design showed a good OR logic output response with the inputs, and acceptable output ranged from around 4.5 to 4.8 V with 5 V HIGH inputs. The results from this OR gate characterization may assist in developing the logic gate for device integration and may act as a reference for future complex integrated circuit design.
  • Publication
    Temperature effects on electrical and structural properties of MEH-PPV/PEIE OLED Device
    ( 2020-06-16)
    Nurul Afiqah Nor Ismail
    ;
    Safizan Shaari
    ;
    Mohd Fairus Ahmad
    ;
    Norhayati Sabani
    ;
    Nurjuliana Juhari
    ;
    Nor Farhani Zakaria
    This paper explores the performance of configuration ITO/MEH-PPV/PEIE/Al OLED under the variations of temperature. The MEH-PPV and MEH-PPV/PEIE thin film were deposited on ITO substrates using spin coating technique with fixed spin speed of 3000 rpm and baked at low temperature ranging from 90 °C to 180 °C, respectively. The surface roughness values for MEH-PPV and MEH-PPV/PEIE films were analysed using AFM with 5 μm ' 5 μm scanning area. The roughness of MEH-PPV thin films were reduced from 2.825 nm to 1.625 nm when temperature increased. Contrary to MEH-PPV/PEIE films where the roughness increased linearly up to 3.397 nm when the temperature increased. The maximum absorption peak spectrum obtained from UV-Visible (UV-Vis) was found at 500 nm to 510 nm when baked temperature were varied. Furthermore, the turn on voltage from J-V characteristics gives no specific pattern across different temperature and agreed with the trend of surface roughness values. The turn-on voltage at T = 150 °C gives the lowest value of 3 V. Overall, the variations of low temperature gives an effects on structural and electrical properties of this OLED configuration.
  • Publication
    Silicon Self-Switching Diode (SSD) as a Full-Wave Bridge Rectifier in 5G Networks Frequencies
    ( 2022-12-01)
    Yi Liang T.
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Singh A.K.
    The rapid growth of wireless technology has improved the network’s technology from 4G to 5G, with sub-6 GHz being the centre of attention as the primary communication spectrum band. To effectively benefit this exclusive network, the improvement in the mm-wave detection of this range is crucial. In this work, a silicon self-switching device (SSD) based full-wave bridge rectifier was proposed as a candidate for a usable RF-DC converter in this frequency range. SSD has a similar operation to a conventional pn junction diode, but with advantages in fabrication simplicity where it does not require doping and junctions. The optimized structure of the SSD was cascaded and arranged to create a functional full-wave bridge rectifier with a quadratic relationship between the input voltage and outputs current. AC transient analysis and theoretical calculation performed on the full-wave rectifier shows an estimated cut-off frequency at ~12 GHz, with calculated responsivity and noise equivalent power of 1956.72 V/W and 2.3753 pW/Hz1/2, respectively. These results show the capability of silicon SSD to function as a full-wave bridge rectifier and is a potential candidate for RF-DC conversion in the targeted 5G frequency band and can be exploited for future energy harvesting application.
  • Publication
    Modification of Photoanode Surface Structure via Image Analysis on Organic Polymer Material based for Dye-Sensitized Solar Cell (DSSC) Applications
    ( 2021-12-01)
    Rosli N.
    ;
    Norhayati Sabani
    ;
    Mohd Fairus Ahmad
    ;
    Azidin M.A.M.
    ;
    Nurjuliana Juhari
    ;
    Zakaria N.F.
    ;
    Mohd Natashah Norizan
    ;
    Safizan Shaari
    In this study, the experiment on the modification of the photoanode with organic polymer material as copolymer template for dye-sensitized solar cell (DSSC) applications has been conducted. The two organic copolymer templates are polystyrene sphere (PS) and poly[2-methoxy-5(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). The modification photoanodes were made using Dr. Blade’s method. These organic copolymer templates were added to improve the surface of the mesoporous titanium dioxide (TiO2) layer, which is used as the main component in DSSC photoanode. The unmodified TiO2 photoanode has poor aggregation and porosity of TiO2. The addition of either MEH-PPV or PS sphere to the photoanode layer was found to affect the surface of mesoporous TiO2 in terms of porosity, particle size distribution and shape. The analysis of the TiO2 modification was conducted using an image analysis processing method via a 2D scanning electron microscope (SEM) image. The image analysis processing method used was the ImageJ program. The DSSC of modified photoanode is fabricated using metal complex dye, Ruthenium (N719) dye. The data collected from the ImageJ program showed that by adding organic copolymer templates into TiO2, the porosity of TiO2 decreased from 45 % to 42 %. From the photovoltaic analysis obtained, the J-V characteristic is recorded with the photoanode of TiO2 mixed with 1.00 wt% MEH-PPV gave the highest efficiency, which is 0.01 % with the following parameters – Voc = 0.43 V, Jsc = 0.17 mA/cm2 and FF = 0.20. Meanwhile, the photoanode of TiO2 mixed with 0.50 wt% PS sphere gave the highest efficiency which is 0.08 % with the following parameters – Voc = 0.39 V, Jsc = 0.86 mA/cm2 and FF = 0.25.