Zarimawaty Zailan
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Zarimawaty Zailan
Official Name
Zarimawaty, Zailan
Alternative Name
Zailan, Z.
Zailan, Zarimawaty
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Scopus Author ID
55603553500
Researcher ID
EHB-9502-2022

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  • Publication
    Fabrication and simulation of silicon nanowire pH sensor for Diabetes Mellitus detection
    ( 2023-04)
    C. Y. Chean
    ;
    Mohammad Nuzaihan Md Nor
    ;
    Mohamad Faris Mohamad Fathil
    ;
    M. I. Hashim
    ;
    Nur Hamidah Abdul Halim
    ;
    Zarimawaty Zailan
    ;
    Mohd Khairuddin Md Arshad
    ;
    Syamsul Syahrun Awang@Hashim
    ;
    Rozaimah A.T
    Diabetes Mellitus (DM) is a disease failed to control the balance of blood sugar level due to lack of insulin thereby it effect human health. In Malaysia, there are around 3.9 millions people aged 18 years old and above have diabetes according to National Health and Morbidity Survey 2019. Silicon Nanowire is a nanostructure which has ultra-high sensitivity and non-radioactive that has potential given good performances when applied on pH sensor and biosensor. Silicon nanowire pH sensor and biosensor is an electronic sensor that investigated to improve the sensitivity and accuracy for detecting DM. This project consists of two parts, which are fabrication of silicon nanowire pH sensor and simulation of silicon nanowire biosensor as preliminary study. In fabrication, silicon nanowire of pH sensor is fabricated by conventional lithography process, reaction ion etching (RIE) and metallization to achieved the width of 100 nm silicon nanowire. The pH6, pH7, pH10 and DI water as analytes to analysis the current-voltage (I-V) characteristics of silicon nanowire pH sensor. In second part, the silicon nanowire biosensor as preliminary study is done simulation by Silvaco ATLAS devices simulator. The silicon nanowire with 30 nm in height and 20 nm in width of biosensor is designed and simulated to analyze the performance in terms of sensitivity. I-V characteristics of silicon nanowire biosensor according to different concentration of negative interface charge is determined. The negative interface charge represent as the Retinol Binding Protein 4 (RBP4) which is used to diagnose DM. The I-V characteristic based on the change in current, resistance and conductance to determine sensitivity. Lastly, the sensitivity of silicon nanowire pH sensor obtained 23.9 pS/pH while the sensitivity of simulated silicon nanowire biosensor obtained 3.91 nS/e.cm2. The results shown the more negative charge of concentration analyte attached on surface silicon nanowire has been accumulated more current flow from drain terminal to source terminal. It leads to the resistance becomes highest and obtained good sensitivity. In summary, the silicon nanowire pH sensor exhibited good performance and high sensitivity in detection pH level. The simulated silicon nanowire biosensor is capable of detecting biomolecular interactions charges to obtained high sensitive and accuracy result.
  • Publication
    Silicon nanowire biosensors for diabetes mellitus monitoring
    ( 2024-10)
    M. Shaifullah A. S
    ;
    J. Jumat
    ;
    Mohammad Nuzaihan Md Nor
    ;
    J. N. Ismail
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Nur Hamidah Abdul Halim
    ;
    Zarimawaty Zailan
    ;
    Mohd Khairuddin Md Arshad
    ;
    M. Syamsul
    ;
    Rozaimah A. T
    The main goal of this research is the development of a label-free biosensor for the detection of diabetes mellitus (DM) using the target molecule retinol-binding protein 4 (RBP4). The enzyme-linked immunosorbent assay (ELISA) approach, currently used to detect DM, is time-consuming and difficult. As a result, label-free biosensors are being considered as an alternative. In this research, silicon nanowires (SiNWs) were selected as the transducer for this biosensor due to their low cost, real-time analysis capability, high sensitivity, and low detection limit. The SiNWs were created using conventional lithography, reactive ion etching (RIE), and physical vapor deposition (PVD), and then dripped with a gold nanoparticle solution to create gold-decorated SiNWs. The surface of the gold-decorated SiNWs was functionalized using 3-aminothiophenol and glutaraldehyde solutions before being immobilized with DM RBP4 antibodies and targets. The electrical characterization of the gold nanoparticle decorated SiNWs biosensor revealed good performance in DM detection. The pH tests confirmed that the SiNWs acted as a transducer, with current proportional to the DM RBP4 concentration. The estimated limit of detection (LOD) and sensitivity for detecting DM RBP4 binding were 0.076 fg/mL and 8.92 nA(g/mL)-1, respectively. This gold nanoparticle decorated SiNWs biosensor performed better than other methods and enabled efficient, accurate, and direct detection of DM. The SiNWs could be used as a distinctive electrical protein biosensor for biological diagnostic purposes. In conclusion, gold nanoparticle deposition offers effective label-free, direct, and high-accuracy DM detection, outperforming previous approaches. Thus, these SiNWs serve as novel electrical protein biosensors for future biological diagnostic applications.
  • Publication
    Application of Taguchi method in optimization of structural parameters in self-switching diode to improve the rectification performance
    ( 2020-01-08)
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Muammar Mohamad Isa
    ;
    Zarimawaty Zailan
    ;
    Mokhar M.B.M.
    ;
    Juhari N.
    This paper presents the use of Taguchi method in the optimization process of a Self-switching Diode (SSD) as a Terahertz rectifier to obtain the optimal parameters for rectification. The rectification performance is mainly contributed by a parameter known as curvature coefficient, γ which is derived from the current-voltage (I-V) behavior of the device and can be altered by varying the device's geometrical structure. The parameters involved are the channel length, channel width and trenches width of the device, and the rectification performance are observed based on the peak of γand its corresponding bias voltage. Using Taguchi method for design of experiment (DOE), effects on the interaction among these parameters are investigated by employing the orthogonal array and evaluation of the signal-to-noise (S/N) ratio both in the peak of γand its corresponding bias voltage. The proposed parameters using this method showed γ peak of 32 V-1 and 30 V-1 at DC bias of 30 mV and zero-bias, respectively.
  • Publication
    Nanoparticle-based biosensors for detection of heavy metal ions
    ( 2023-10)
    Y. J. Beh
    ;
    Mohammad Nuzaihan Md Nor
    ;
    Syarifah Norfaezah Sabki
    ;
    S. B. Chia
    ;
    C. H. Ng
    ;
    C. C Ong
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Zarimawaty Zailan
    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.
      1  9
  • Publication
    Self-switching diodes as RF rectifiers: Evaluation methods and current progress
    ( 2019-06-01)
    Zakaria N.
    ;
    Shahrir Rizal Kasjoo
    ;
    Isa M.
    ;
    Zarimawaty Zailan
    ;
    Arshad M.
    ;
    Sanna Taking
    In the advancement of the Internet of Things (IoT) applications, widespread uses and applications of devices require higher frequency connectivity to be explored and exploited. Furthermore, the size, weight, power and cost demands for the IoT ecosystems also creates a new paradigm for the hardware where improved power efficiency and efficient wireless transmission needed to be investigated and made feasible. As such, functional microwave detectors to detect and rectify the signals transmitted in higher frequency regions are crucial. This paper reviewed the practicability of self switching diodes as Radio Frequency (RF) rectifiers. The existing methods used in the evaluation of the rectification performance and cut-off frequency are reviewed, and current achievements are then concluded. The works reviewed in this paper highlights the functionality of SSD as a RF rectifier with design simplicity, which may offer cheaper alternatives in current high frequency rectifying devices for application in low-power devices.
  • Publication
    Design and characterization of self-switching diode and planar barrier diode as high-frequency rectifiers
    ( 2018)
    Zarimawaty Zailan
    The development of high-speed rectifying devices has become one of major research areas which can be utilized in many applications, including radio-frequency (RF) and detection systems. Examples of these devices are Schottky diode and planar-doped barrier diode. However, all these excellent devices require a very challenging in fabrication process due to their complex structures and a precise doping concentration for each critical layers which are relatively high cost. The prospects of using electronic devices with planar structure are therefore become increasingly promising. These planar devices provide additional advantages of being not only simple but also able to operate at high frequencies. As such, in this research work, the feasibility of utilizing two silicon-based planar nanodevices of self-switching diode (SSD) and planar barrier diode (PBD) for microwave and terahertz rectification has been demonstrated using simulations. SSD has recently been demonstrated as room-temperature rectifiers operating at terahertz frequencies. In this research work, the rectifying performance of SSD is evaluated using a parameter known as the curvature coefficient, derived from the current-voltage (I-V) characteristic of the device. The effects of varying the geometrical structure and the insulator dielectric relative permittivity (from 1 – 9.3) of SSD on the curvature coefficient of the device are studied and analyzed by means of a two-dimensional device simulator. The simulations are also performed under temperature range of 250 – 500 K. The results show that the highest cut-off frequency attained in this research work is approximately 19 GHz, operating at unbiased condition. By implementing similar simulation settings used in demonstrating siliconbased SSDs, a new unipolar planar nanodiode as a rectifier is introduced and developed in this research work. This new device is referred as PBD which has a funnel-shaped geometrical channel that allows current to flow across the device. At zero bias, the nonuniform depletion region, developed at the neck of the funnel-shape channel due to surface charges at semiconductor/insulator interface, is predicted to create an energy barrier along the channel with asymmetrical profile. An external voltage applied across a PBD is expected to produce different height of the energy barrier depending either the voltage given is positive or negative. As a result, a nonlinear I-V characteristic is realized which can be utilized in signal rectification. This operating principle of PBD has been demonstrated and validated in the simulations of this research work. It has also been described using thermionic emission theory which may govern the flow of current across the device. Similar to SSD, the rectification performance of PBD is characterized and evaluated based on the curvature coefficient and cut-off frequency of the device. By varying the geometrical design and insulator dielectric relative permittivity (from 1-9.3) of PBD, curvature coefficient of the device can be optimized in order to improve the rectification performance. The highest cut-off frequency obtained in the simulation of this work is approximately 0.8 THz. Both SSD and PBD have a planar architecture that can therefore be realized in a single lithography step which makes the whole fabrication process of the devices simpler, faster and at lower cost when compared with other conventional electronic devices.
      2  3
  • Publication
    Fabrication and characterization of engineered tunnel barrier for nonvolatile memory application
    ( 2012)
    Zarimawaty Zailan
    Non-volatile memory is a solid state memory device that can retain the stored information even when the power is turned-off; examples of a variety of ROMs and Flash Memory. Based on the charge storing mechanism, it can be divided into two main classes; floating gate and charge trapping devices. The most widely used device structure in contemporary memory technology is of a floating gate type. In this type of memory, electrons were transferred from the substrate to the floating gate, and vice versa in memory operations known as write and erase. For NAND Flash Memory architecture, these electrons transfer were carried out using tunneling mechanism known as Fowler-Nordheim tunneling, and its efficiency would determine the performance of a memory device. This mechanism takes place via ultra-thin dielectric layer, known as tunnel dielectric, which physically and electrically separates the floating gate from the substrate. Traditionally, thermally grown SiO2 thickness ranging from 5 nm to 10 nm is used as the tunnel dielectric. The 5 nm thicknesses is considered the intrinsic tunnel oxide limit, below which various leakages such as stress induced leakage current (SILC) and direct tunneling start to became a prominent limiting factors. Several efforts have been made to improve the flash memory cell performance by replacing the traditional SiO2 with various dielectric such as Oxynitride, and combinations of High-k materials. This study focuses on the Variable Oxide Thickness (VARIOT) approach of engineered tunnel barrier where the asymmetrical VARIOT structure with the effective oxide thickness (EOT) ranging from 6 nm to 14 nm were studied in the form of MOS capacitor structure. The tunneling current density in the VARIOT structure yield 108 A/cm2 at 15V programming voltage, compared to 105 A/cm2 for the conventional tunnel barrier with the same programming voltage. The results show that asymmetrical VARIOT tunnel barrier would significantly improves the floating gate memory-cell performance.
      3  8
  • Publication
    Effect of channel length to the frequency response of Si-based Self-Switching Diodes using two-dimensional simulation
    ( 2020-12-18)
    Zarimawaty Zailan
    ;
    Shahrir Rizal Kasjoo
    ;
    Nurul Bariah Idris
    ;
    Khairul Affendi Rosli
    ;
    Nor Farhani Zakaria
    ;
    Muammar Mohamad Isa
    A planar nanodevice, known as the self-switching diode (SSD) which can be exploited as a high-speed rectifier in a wide range of applications. The non-linearity in the I-V characteristic of the SSD structure has been aimed for rectification application at GHz frequencies is reported. In this work simulation has been conducted on Si-based SSD structure with 230 nm L-shaped channels using ATLAS device simulator under the channel length range of 0.5 μm to 1.3 μm. Furthermore, the validity of the cut-off frequency has also been described using a theoretical value of f t at zero bias. The results showed that the optimization in the channel length of the SSD can assist the high cut-off frequency of SSD rectifying behavior to efficiently operate as microwave rectifier.
      7  2
  • Publication
    Effect of channel length to the frequency response of Si-based Self-Switching Diodes using two-dimensional simulation
    ( 2020-12-18)
    Zarimawaty Zailan
    ;
    Shahrir Rizal Kasjoo
    ;
    Idris N.B.
    ;
    Rosli K.A.
    ;
    Zakaria N.F.
    ;
    Muammar Mohamad Isa
    A planar nanodevice, known as the self-switching diode (SSD) which can be exploited as a high-speed rectifier in a wide range of applications. The non-linearity in the I-V characteristic of the SSD structure has been aimed for rectification application at GHz frequencies is reported. In this work simulation has been conducted on Si-based SSD structure with 230 nm L-shaped channels using ATLAS device simulator under the channel length range of 0.5 μm to 1.3 μm. Furthermore, the validity of the cut-off frequency has also been described using a theoretical value of f t at zero bias. The results showed that the optimization in the channel length of the SSD can assist the high cut-off frequency of SSD rectifying behavior to efficiently operate as microwave rectifier.
  • Publication
    Fabrication and simulation of silicon nanogaps pH sensor as preliminary study for Retinol Binding Protein 4 (RBP4) detection
    ( 2025-01)
    M. I. Hashim
    ;
    Mohammad Nuzaihan Md Nor
    ;
    Mohamad Faris Mohamad Fathil
    ;
    M. Shaifullah A.S
    ;
    C. Y. Chean
    ;
    Nur Hamidah Abdul Halim
    ;
    Zarimawaty Zailan
    ;
    Mohd Khairuddin Md Arshad
    ;
    Muzamir Isa
    ;
    Ayu Wazira Azhari
    ;
    M. Syamsul
    ;
    Rozaimah A.T.
    In this research, a silicon nanogap biosensor has the potential to play a significant role in the field of biosensors for detecting Retinol Binding Protein 4 (RBP4) molecules due to its unique nanostructure morphology, biocompatibility features, and electrical capabilities. Additionally, as preliminary research for RBP4, a silicon nanogap biosensor with unique molecular gate control for pH measurement was developed. Firstly, using conventional lithography followed by the Reactive-ion etching (RIE) technique, a nanofabrication approach was utilized to produce silicon nanogaps from silicon-on-insulator (SOI) wafers. The critical aspects contributing to the process and size reduction procedures were highlighted to achieve nanometer-scale size. The resulting silicon nanogaps, ranging from 100 nm to 200 nm, were fabricated precisely on the device. Secondly, pH level detection was performed using several types of standard aqueous pH buffer solutions (pH 6, pH 7, pH 12) to test the electrical response of the device. The sensitivity of the silicon nanogap pH sensor was 7.66 pS/pH (R² = 0.97), indicating that the device has a wide range of pH detecting capacity. This also includes the silicon nanogap biosensor validated by simulation, with the sensitivity obtained being 3.24 μA/e.cm² (R² = 0.98). The simulation of the sensitivity is based on the interface charge (Qf) that represents the concentration of RBP4. The results reveal that the silicon nanogap biosensor has excellent characteristics for detecting pH levels and RBP4 with outstanding sensitivity performance. In conclusion, this silicon nanogap biosensor can be used as a new electrical RBP4 biosensor for biomedical diagnostic applications in the future.