Syarifah Norfaezah Sabki
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Preferred name
Syarifah Norfaezah Sabki
Official Name
Syarifah Norfaezah, Sabki
Alternative Name
Sabki, S. N.
Sabki, Syarifah N
Norfaezah Sabki, S
Sabki, Syarifah Norfaezah Binti
Main Affiliation
Scopus Author ID
35090423100
Researcher ID
GBY-6284-2022

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  • Publication
    Surface Morphology Analysis of graphene transfer on SiO2 with BPA aptasensor detection using Electrochemical Impedance Spectroscopy
    ( 2023-01-01)
    Shukri N.I.A.
    ;
    Norhayati Sabani
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Syarifah Norfaezah Sabki
    ;
    Ruslinda A. Rahim
    ;
    Halim N.H.A.
    ;
    Ismail N.S.
    Bisphenol A or BPA is one of the highest produced chemicals in the world. The production of polycarbonate plastic and epoxy resin are used to make variety of consumer goods and it is frequently employed BPA as a raw material. BPA is one of the endocrine disruptors which is related to a wide range of adverse health effects that can cause reproductive disorders and many kinds of cancers. In the work, the novelty of electrochemical sensor of BPA was constructed on a graphene modified electrode using graphene transfer method. In this work, High-power microscope and scanning electron microscopy were used to study the production and characterization of the graphene, with two significant mapping graphene at 20% and 80%. The existence of graphene on silicon oxide was analyzed using Raman Spectroscopy while the composition of the materials was analyze using Fourier-Transform Infrared Spectroscopy. In this analysis, both analysis data from Raman and FTIR clearly shown that 80% mapping graphene is the best option which resulting to the high surface coverage. The electrochemical performance of the mapping 80% graphene electrode was examined using Electrochemical Impedance Spectra. The increase in charge transfer resistance (Rct) both before and after the addition of BPA denotes the development of the charge at the electrode surface. The equivalent circuit shows the Rct of graphene increased from 0.4 k Ω to 1.2 k Ω and drastically increased to 300 kΩ when the device was introduced with BPA due to the existence of a negative charge carrier and the repelling contact.
  • Publication
    A review: synthesis and mechanism of growth of the carbon nanotubes (CNTs) – graphene hybrid material and its application as electrodes
    ( 2023-07)
    Mishthafiyatillah
    ;
    Syarifah Norfaezah Sabki
    ;
    Norzilah Abdul Halif
    ;
    Muhammad Asri Idris
    ;
    Norashiken Othman
    The CNTs–graphene hybrids have many advantages and potential for use in a wide range of electronic applications as electrodes. The CNTs–graphene hybrid structure outperforms the structure of each material in terms of characteristics and performance. There are several methods to grow CNTs. This paper reviews the chemical vapor deposition (CVD) method used to synthesize CNTs–graphene hybrid material. This paper discusses the processes and growth parameters of the synthesis of the CNTs-graphene hybrid. This paper also discusses the growth mechanism and kinetics of CNTs. In addition, the potential and performance of CNTs–Graphene hybrid material as electrodes in batteries are also reviewed.
  • Publication
    Impact of different doping concentrations on the digital and analog FoM of a junctionless transistor
    ( 2020-01-08)
    Noraini Othman
    ;
    Ring, Tan Shin
    ;
    Syarifah Norfaezah Sabki
    The miniaturization of transistors causes many challenges in producing high quality junctions for a conventional transistor. As conventional transistors getting smaller in size, there are several critical challenges such as low on-state current, Ion and high gate leakage current, Ioff. Junctionless transistor (JLT) is an alternative to conventional transistor with junctions as it is uniformly doped and has no doping concentration gradients. This work embarks to study the impact of various doping concentrations towards the digital and analog figure-of-merit (FoM) of a JLT. Simulations of a junctionless transistor were carried out by using Silvaco ATLAS TCAD Tools for gate length of 25 nm. It is found that the best doping concentration is of 1 × 1018 cm-3 as it produces the highest Ion while maintaining low Ioff of 1.31 × 10-06 A and 6.94 × 10-11 A respectively in the digital realm. In terms of analog FoM, the best doping concentration is also found to be of 1 × 1018 cm-3 as it produces the highest cut-off frequency, ft of 227 GHz.
  • Publication
    Hexagonal enhanced porous GaN with delayed integrated pulse electrochemical (iPEC) etching
    ( 2024-10)
    Nurul Syuhadah Mohd Razalia
    ;
    Alhan Farhanah Abd Rahim
    ;
    Nur Sabrina Mohd Hassan
    ;
    Rosfariza Radzali
    ;
    Ainorkhilah Mahmood
    ;
    Syarifah Norfaezah Sabki
    ;
    Irni Hamiza Hamzah
    ;
    Mohaiyedin Idris
    ;
    Mohamed Fauzi Packeer Mohamed
    This present study investigates the effect of time delay (Td) on the formation of porous GaN (P-GaN) using integrated pulse electrochemical (iPEC) etching. Porous GaN (P-GaN) was formed by etching an N-type GaN wafer with a 4% KOH electrolyte for 60 minutes under an ultraviolet (UV) lamp at a current density of 80 mA/cm2. A Td of 120 minutes was applied before electrochemically etching the P-GaN sample. The top view image of the field emission scanning electron microscopy (FESEM) revealed a significant difference when a Td was applied. A dense and uniform hexagonal P-GaN was obtained from the Td iPEC sample, while the non-Td sample exhibited a multi-layered hexagonal porous structure with unfinished pore-etched areas. Higher porosity and deeper pores were observed in the Td sample. Intense high-resolution X-ray diffraction (HR-XRD) peak intensity was observed in the Td iPEC sample with a lower full width half maximum (FWHM), indicating that the sample had better crystallinity. The Raman spectra of the sample anodized with a Td exhibited higher Raman peak intensity and a slight shift to a higher frequency concerning as-grown GaN, indicating better crystallinity and a tensile stress relaxation of 0.24 GPa. Post etching, a blue shift of the photoluminescence (PL) peak, from 364 nm (as-grown GaN) to 363 nm (P-GaN), was observed, and a small PL peak started to form around 385 nm compared to the as-grown GaN due to the relaxation of the tensile stress, which modified the bandgap. The PL peak intensity of the Td sample was higher than the non-Td sample, indicating that the porosity and uniformity allowed more light interaction with the material, resulting in more efficient photon absorption and emission. The results indicated that potentially efficient optoelectronics devices can be fabricated on a P-GaN using a combination of electroless and electrochemical etching of the GaN epitaxial layer.
  • Publication
    A controlled growth of carbon nanofibers (CNFs) on graphene
    ( 2023-12)
    Mishtha Fiyatillah
    ;
    Syarifah Norfaezah Sabki
    ;
    Norzilah Abdul Halif
    ;
    L K Wisnu Kita
    ;
    Muhammad Asri Idris
    ;
    Noraini Othman
    ;
    A F Abd Rahim
    Carbon nanofibers (CNFs) have superior properties such as high conductivity, good mechanical strength, high specific surface area, and chemical stability. CNFs-graphene hybrid material can be used as a high-quality electrode in electronics applications. In the CNFs on graphene synthesis, the growth parameters must be well controlled. This work observes the evolution of the CNF's growth on graphene on Ni at reaction temperatures of 800oC and 860oC and at different reaction times of 30 min, 60 min, and 120 min. This research aims to find suitable conditions for obtaining controllable growth of CNFs on graphene. Based on the SEM measurement, it was found that the 860oC reaction temperature at 60 min and 120 min reaction time led to longer and smaller widths of CNFs with high coverage and distribution on graphene. The CNFs on graphene formation were confirmed by the XRD analysis.
  • Publication
    Performance Analysis of a Double-Gate Junctionless Transistor with Varied Doping and Gate Underlap using Device Simulator
    ( 2021-01-01)
    Afiqah Nasir N.N.
    ;
    Noraini Othman
    ;
    Syarifah Norfaezah Sabki
    ;
    Farhanah Abd Rahim A.
    In this work, the impact of doping concentrations and gate underlap towards the electrical performance of a double-gate junctionless transistor (DG-JLT) were investigated using three-dimensional device simulator. The results show that the parameter of doping concentrations (Nd) has a greater impact towards the electrical performance of the transistor as compared to the gate underlap length (Lun). This can be seen in the results of leakage current (Ioff) and Drain-Induced Barrier Lowering (DIBL), where variations in Nd causes differences as high as 5 decades to be obtained for Ioff together with significant increase in DIBL. In overall, it was found that Nd=1×1018 cm-3 provides the best results in terms of the lowest DIBL and Ioff and the highest Ion/Ioff ratio. Meanwhile, longer Lun is found to give better electrical characteristics. The results obtained in this work can be used to further determine the most significant factors among the structural and material parameters that influence the electrical characteristics of a JLT.
  • Publication
    Fabrication of Graphene Electrode via Graphene Transfer Method for Bisphenol A (BPA) Detection
    ( 2021-01-01)
    Shukri N.I.B.A.
    ;
    Norhayati Sabani
    ;
    Ruslinda A. Rahim
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Syarifah Norfaezah Sabki
    ;
    Nur Hamidah Abdul Halim
    ;
    Nur Syakimah Ismail
    Exposure of BPA is a concern as BPA can seep into food or beverages from containers and can possibly effects on human health especially endocrine systems. An electrochemical-based aptasensor utilizing graphene was developed in detecting endocrine disrupting compound Bisphenol A (BPA, 4,4'-(propane-2,2-diyl) diphenol). The graphene modified electrode was developed via graphene transfer. Fabrication and characterization of graphene transfer was studied in this paper using Scanning Electron Microscopy (SEM) and High-Power Microscope (HPM). In this research, the investigation of interfacial characteristic modified graphene with aptasensor and recognition of BPA with aptasensor had been done using electrochemical impedance spectroscopy (EIS). The increment of charge transfer resistance (Rct) before and after recognition of BPA denoting the accumulation of charge at the electrode surface in this research.
  • Publication
    The impact of strained layer superlattice (SLS) to the emission and internal quantum efficiency (IQE) of a GaN LED
    ( 2020-01-08)
    Min Tain Shi
    ;
    Syarifah Norfaezah Sabki
    ;
    Noraini Othman
    Gallium nitride (GaN) light emitting diode (LED) has been used as highly efficient solid-state light sources to radiate a wide range of wavelengths in the visible spectrum. Larger currents drive bright LEDs, causes reduced efficiency which known as LED droop. Insertion of strained-layer superlattice (SLS) in GaN LED gives uniform electron distribution, lead to high emission and efficiency. The primary aim of this work is to investigate the operation of LED with the inclusion of SLS by simulation. The GaN LED was designed in cylindrically symmetrical configuration with the insertion of the InGaN/GaN SLS of 3 nm thick. This work investigates the effect of different number of SLS layers, which is represented by 1, 2 and 3 periods of SLS, which represent the total SLS thicknesses of 3 nm, 6 nm and 9 nm respectively. A GaN cylindrical chip of 700 nm diameters was designed with p- and n-type doped active region. The results has shown that the efficient operation of the LED can occur within the lowest current of 0.1 mA for the 2 periods of SLS with the total emission rate displayed linearly increased. A sharp decline of internal quantum efficiency (IQE) droops close to zero despite the increasing current was significantly observed for the 2 periods of SLS, which has also resulted to operate at a low turn-on voltage of 2.5 V. However, it was found that higher than 3 periods with SLS total thickness of higher than 6 nm cause the pn junction failure with no emission.
  • Publication
    A Review: Synthesis and Mechanism of Growth of the Carbon Nanotubes (CNTs) – Graphene Hybrid Material and its Application as Electrodes
    ( 2023-07-01)
    Mishthafiyatillah
    ;
    Syarifah Norfaezah Sabki
    ;
    Norzilah Abdul Halif
    ;
    Muhammad Asri Idris
    ;
    Noraini Othman
    The CNTs–graphene hybrids have many advantages and potential for use in a wide range of electronic applications as electrodes. The CNTs–graphene hybrid structure outperforms the structure of each material in terms of characteristics and performance. There are several methods to grow CNTs. This paper reviews the chemical vapor deposition (CVD) method used to synthesize CNTs–graphene hybrid material. This paper discusses the processes and growth parameters of the synthesis of the CNTs-graphene hybrid. This paper also discusses the growth mechanism and kinetics of CNTs. In addition, the potential and performance of CNTs–Graphene hybrid material as electrodes in batteries are also reviewed.
      1
  • Publication
    Correlation between crystal structure and thermal reaction of TiOâ‚‚ - Graphene Oxide
    ( 2021-04)
    Siti Kartom Kamarudin
    ;
    Muhammad Asri Idris
    ;
    Nur Farhana Diyana Mohd Yunos
    ;
    Banjuraizah Johar
    ;
    Ho Li Ngee
    ;
    Syarifah Norfaezah Sabki
    ;
    Suhaimi Illias
    TiO₂ - Graphene oxide (GO) (GO = 0-1.0wt %) powders were synthesised using sol-gel method and annealed at 500°C. The samples were then characterised using X-ray diffraction (XRD). The additional of GO gave significant influence on the crystal structure of TiO₂. The lattice parameter of TiO₂ were increased with decreasing GO concentration. The unit cell volume of TiO₂-GO annealed in N2 decreased with the oxygen occupancy. In contrary, the TiO₂-GO annealed in O₂ has an increase in O₂ occupancies in the lattice that was nearly proportional to its unit cell volume. A continuous weight loss was recorded by TGA at a temperature range of T= 30 - 1000°C that were associated with H2O, C-H and C-O species. It is concluded that the Ti-O-C and Ti-C bonds were formed for samples annealed in O₂ and N2 respectively. The weight loss of TiO₂-GO annealed in O₂ is lesser than that annealed in N2 for same concentration additional GO into TiO₂.
      3  8