Syarifah Norfaezah Sabki
Thumbnail Image
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

Research Output

Filters

6 1
Reset filters

Settings
Now showing 1 - 10 of 18
Thumbnail Image
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.

View
Thumbnail Image
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.

View
Thumbnail Image
Publication

A study on the impact of silicon-on-nothing (SON) versus silicon-on-insulator (SOI) on the electrostatic performance of a transistor

2018-12 , Noraini Othman , Syarifah Norfaezah Sabki , Hasnizah Aris

In this work, we investigate the impact of employing silicon-on-nothing (SON) versus silicon-on-insulator (SOI) on the electrostatic performance of a transistor with various ground-plane (GP) structures of Lg = 10 nm through the use of Sentaurus TCAD simulator. The digital figure-of-merit (FoM) of interest includes the results of drain-induced barrier lowering (DIBL) which is a major indicator of a control of short-channel effects (SCEs). It is found that SOI devices produce a lower off-current (Ioff) as compared to SON. In terms of the different GP architectures, the introductions of various GP architectures were found to affect the values of DIBL in SOI whereas the impact on SON is negligible. It can be concluded that GP-B architectures with ground plane underneath the channel areas of SOI is most effective in suppressing substrate depletion effects as evidenced from the lowest DIBL produces.

View
Thumbnail Image
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.

View
Thumbnail Image
Publication

A Controlled Growth of Carbon Nanofibers (CNFs) on Graphene

2023-12-01 , Fiyatillah M. , Syarifah Norfaezah Sabki , Norzilah Abdul Halif , Kita L.K.W. , Muhammad Asri Idris , Noraini Othman , Abd Rahim A.F.

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.

View
Thumbnail Image
Publication

Nanoparticle-based Biosensors for Detection of Heavy Metal Ions

2023-10-01 , Beh Y.J. , Mohammad Nuzaihan Md Nor , Syarifah Norfaezah Sabki , Chia S.B. , Ng C.H. , Ong C.C. , Fathil M.F.M. , Zailan Z.

Heavy metal pollution is one of the most serious environmental problems in the world. Many efforts have been made to develop biosensors for monitoring heavy metals in the environment. Development of nanoparticle-based biosensors is the most effective way to solve this problem. This review presents the latest technology of nanoparticle-based biosensors for environment monitoring to detect heavy metal ions, which are magnetic chitosan biosensor, colorimetric biosensor, and electrochemical biosensor. Magnetic chitosan biosensor acts as a nano-absorbent, which can easily detect and extract poisonous heavy metal ions such as lead ions and copper ions. There are several methods to prepare the chitosan based on the nanoparticle, which are cross-linking, co-precipitation, multi-cyanoguanidine, and covalent binding method. In colorimetric biosensor, gold and silver nanoparticles are commonly used to detect the lead and mercury ions. In addition, this biosensor is very sensitive, fast and selective to detect metal ions based on the color change of the solution mixture. Meanwhile, electrochemical biosensor is widely used to detect heavy metal ions due to a simple and rapid process, easy, convenient and inexpensive. This biosensor is focused on the surface area, which leads to significant improvement in the performance of devices in terms of sensitivity. The wide surface area can affect the performance of the biosensor due to a limited space for operation of electrode. Therefore, reduced graphene oxide is a suitable material for making the electrochemical biosensor due to a wide surface area, good conductivity and high mechanical strength. In conclusion, these three technologies have their own advantages in making a very useful biosensor in the detection of heavy metal ions.

View
Thumbnail Image
Publication

Carbon Nanofibers (CNFs) Synthesis on Graphene/Ni Thin Film: An Analysis on the Effect of Carrier Gas Flow Rate

2023-01-01 , Fiyatillah M. , Syarifah Norfaezah Sabki , Norzilah Abdul Halif , Kita L.K.W. , Jun H.Q. , Muhammad Asri Idris , Noraini Othman , Abd Rahim A.F.

The pursuit of high-performance materials for interconnects and electrodes in various electronic applications has led to the exploration of carbon nanotubes (CNTs)-graphene hybrid materials due to their potential to surpass copper (Cu) in terms of thermal conductivity. This study aimed to grow CNTs on graphene. However, the applied growth parameters led to the formation of carbon nanofibers (CNFs) on graphene. CNFs-graphene hybrids may have lower thermal conductivity compared to CNTs-graphene hybrids. This investigation aims to understand the growth evolution of the CNFs at a varied carrier gas flow rate. This work investigates the CNFs' growth on graphene on a nickel (Ni) thin film substrate under a growth temperature of 860°C in 2 hours. By varying the gas flow rate, this research aims to discern the optimal conditions for achieving controllable CNFs growth on graphene. This work found that the higher carrier gas flow rate led to better formation of CNFs with a more uniform coverage and smaller width. The XRD results confirm the formation of CNFs on graphene.

View
Thumbnail Image
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.

View
Thumbnail Image
Publication

Progression in the growth of cylindric nanostructures: carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on graphene

2022-12 , Syarifah Norfaezah Sabki , Norzilah Abdul Halif , H.A. Hanafi , Mishthafiyatillah , Muhammad Asri Idris , Norashiken Othman , Mohamad Nazri Abdul Halif , Norhayati Sabani , A.F. Abd Rahim

The combination of carbon nanotubes (CNTs) and graphene produce a CNTs-graphene hybrid material with excellent electrical and mechanical properties that improved from their single form. This CNTs-graphene hybrid material has the potential to be used as electrodes and interconnects as it has better properties compared to copper (Cu). This work intended to grow CNTs on graphene using a CVD technique. The growth process used graphene on a Cu substrate with ferrocene as the catalyst, acetone as the carbon precursor and reactor temperature of 800oC. However, the process has unintentionally grown carbon nanofibers (CNFs). To observe the progression in the growth of CNTs and CNFs on graphene, the effect of growth reaction time is crucial. Hence, this work investigates the growth progression of the CNTs and CNFs on graphene based on different reaction times of 10 min, 20 min, 30 min and 60 min. It was found that the agglomeration of carbon is incomplete at 10 min reaction time and produced cylindric nanostructures. A further reaction time of 20 min and 30 min has significantly changed the size of the cylindric nanostructures into CNTs and CNFs with a very slight difference in the size, density, and coverage. The 30 min reaction time produced denser CNTs and CNFs with more uniform size and coverages. A longer reaction time of 60 min led to very long CNFs with an average length of 120 μm. In conclusion, meticulous fine-tuning of the reaction time is required to control the formation of CNTs and CNFs on graphene.

View
Thumbnail Image
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.

View