Nor Farhani Zakaria
Thumbnail Image
Preferred name
Nor Farhani Zakaria
Official Name
Nor Farhani, Zakaria
Alternative Name
Zakaria, N. Fa
Zakaria, N. F.
Zakaria, N.
Main Affiliation
Scopus Author ID
57191032557
Researcher ID
AFT-7132-2022

Research Output

Filters

28
Reset filters

Settings
Now showing 1 - 10 of 28
  • Publication
    A brief overview of detectors used for terahertz imaging systems
    ( 2020-01-08)
    Shahrir Rizal Kasjoo
    ;
    Mohd Mokhar, Mohd Bazli
    ;
    Nor Farhani Zakaria
    ;
    Nurjuliana Juhari
    This paper presents a short review on terahertz imaging systems based on several types of technology used in the terahertz detection schemes. Some commercial products from ThruVision Systems Limited Company have utilized GaAs Schottky diode detector at 0.25 THz to produce passive terahertz images for public and homeland security. On the other hand, TeraSense Group Incorporated Company has developed and invented a ground-breaking technology which employs sensor consisting of a matrix of plasmonic semiconductor detectors in their latest products to generate terahertz images in the 0.1 - 1.0 THz frequency range. Recently, the utilization of two-terminal unipolar nanodiodes, known as the self-switching diodes (SSDs), as terahertz detectors has shown promising results. The planar structure of SSD not only enables the device to operate at high frequencies due to low intrinsic parasitic capacitance, but also allows the realization of the device using only a single lithography step. This makes the fabrication process of SSDs faster, more simple, and at lower cost when compared to other electronic devices such as Schottky diodes. The development and recent achievement of SSDs as terahertz detectors are also presented in this paper.
  • Publication
    Design and simulation of InGaAs-based planar electronic nanodevices as terahertz rectifiers based on curvature coefficient analysis
    ( 2019)
    Nor Farhani Zakaria
    The “Terahertz gap” frequencies between 0.1 to 10 THz possess unique characteristics with a lot of promising application in various fields such as safe imaging, medical and explosive detections. However, limited numbers of optimal (current responsivity, β > 3.5 V-1) detectors and sources in this region leave researchers only a few alternatives in exploring the region. In this work, characterizations using ATLAS device simulator aimed to increase β performance of Self-switching Diode (SSD) and simulations of new planar devices; the Planar Barrier Diode (PBD) and Self-switching Planar Barrier Diode (SSPBD) are reported. The β is mainly contributed by a parameter known as the curvature coefficient, γ which is derived from the current-voltage (I-V) behavior of the device. As such, the γ was analyzed in this work, not only by varying the device’s geometrical structure, but also by implementing different dielectric relative permittivity of the insulating material ranging from 1.0 – 10 under temperature range of 300 – 600 K. The results showed that increased temperature degraded the SSD’s and PBD’s rectifying performance due to increased reverse current which can deteriorate the nonlinearity of the device’s I-V characteristic. For SSD, the γ of ~32 V-1 and 30 V-1 has been achieved at 30 mV and zero-bias, respectively. The cut-off frequency, fc of SSD attained in this work was ~80 GHz, operating at unbiased condition. In addition, an enhanced barrier is introduced in the new PBD device, which contributed to higher switching speed in the channel. The working principle of the new PBD is explained using thermionic emission theory. By employing the optimized structure parameters, the zero-bias γ of ~4 V-1, with peak of ~14 V-1 at 0.10 V bias were achieved. With DC bias of 50 mV to exploit the rectification peak, the fc of the PBD was attained at 270 GHz. In addition, hybrid structure of SSPBD shows improved performance in fc with detection of 360 GHz at zero-bias. Zero-bias γ of ~6 V-1, with peak of ~19 V-1 at 70 mV bias were observed in the SSPBD. The β of >3.5 V-1 in all simulated devices indicates optimal conversion ability as a rectifying device. The results obtained in this work proved the functionality of SSD as mm-wave rectifiers, and the new devices of PBD and SSPBD as THz rectifiers and may assist in future improvement of the devices.
  • 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
    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
    The effect of ZnO photoanode solution ageing to the performance of dye-sensitized solar cell (DSSC)
    ( 2020-01-08)
    Gan Y.K.
    ;
    Nor Farhani Zakaria
    ;
    Ili Salwani Mohamad
    ;
    Mohd Natashah Norizan
    This paper reports the effect of ageing of the zinc oxide (ZnO) solution made of diethanolamine (DEA) and ZnO powder mixture to the performance of DSSCs. The ZnO solution was prepared on day 0 and kept in ambient room temperature for ageing analysis. Two DSSCs were prepared by depositing the ZnO solution on an indium-doped tin oxide (ITO) glass respectively by using doctor-blade technique in a light controlled (dark) surrounding on daily basis for efficiency analysis. Investigation on the nanostructures of the photoanodes was made by varying the ageing days of the ZnO solution between day 0 to 28. The resulting average nanoparticle sizes were in the range of 0.113 μm to 0.960 μm in nanorods shape, which suggests that the solution is homogenous and utilisable throughout 28 days of storage. Efficiency values ranging from 0.95% to 2.05% had been observed on the first hour of the DSSCs made from various aged solution up to 28 days, which proved that 28 days of ageing of ZnO photoanode solution does not affect the performance of DSSCs. The results obtained may assist in the fabrication process and storage of DSSC components in the future.
  • Publication
    Hybrid Statistical and Numerical Analysis in Structural Optimization of Silicon-Based RF Detector in 5G Network
    ( 2022-02-01)
    Yi Liang T.
    ;
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Safizan Shaari
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Singh A.K.
    ;
    Sobri S.A.
    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
    Low-cost tilt monitoring system for spin coater calibration
    ( 2024-02-08)
    King C.Y.
    ;
    Mohd Fairus Ahmad
    ;
    Norhayati Sabani
    ;
    Mohd Natashah Norizan
    ;
    Nor Farhani Zakaria
    ;
    Nurjuliana Juhari
    ;
    Shamsul Amir Abdul Rais
    ;
    Amin M.R.R.M.
    The spin coating process became the most widely used technique in the fabrication industry for thin film coating on a substrate by centrifugal force. Unfortunately, frequent usage of spin coater might induce a tilted surface of the chuck (i.e. the sample holder). A tilted chuck might induce inhomogeneity of the coating layer. Among the machine's calibration techniques, nullifying the tilt before the spin coating process is the most important step. However, to our knowledge, none of the spin coaters was introduced with the chuck's tilt monitoring during the spin coating process. Thus, investigating the discrete condition during the spin coating process is necessary. In this work, the tilt monitoring system for the spin coater was implemented based on an Arduino Uno microcontroller and distance sensor. A spin coater has been implemented to test the tilt surface monitoring during spinning ranges from 350rpm to 1000rpm. The measurement was done under two conditions: flat (0.00 degrees) and tilted (5.71 degrees). The setup was able to measure up to 0.01 degrees of the tilt.
  • 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
    The modelling of SiC Gate Oxide thickness based on thermal oxidation temperatures and durations for high-voltage applications
    (Walailak University, 2023)
    Nuralia Syahida Hashim
    ;
    Banu Poobalan
    ;
    Nor Farhani Zakaria
    ;
    Manikandan Natarajan
    ;
    Safizan Shaari
    This research has shown that the oxide thickness for silicon carbide (SiC) based wide materials can be predicted using regression techniques in wet/dry nitrided or wet/dry non-nitrided thermal oxidation process conditions for high voltage applications by employing 2 different regression techniques: Polynomial and linear regression. The R-squared (R2) and Mean Absolute Percentage Error (MAPE) techniques are used to evaluate the regression models. Furthermore, this work investigates and presents a calculation of gate oxide thickness that is correlated to gate voltage ranges for high voltage applications. In this work, the thermal oxidation process environment is classified into 3 different processing conditions: conventional (dry and wet), dry nitrided (NO,N2O), and wet nitrided (HNO3 vapour). The findings from this study showed that wet oxidation combined with nitrided elements can produce thicker and better-quality gate oxide as compared to conventional dry and wet oxidation techniques. The outcome of this work clearly shows that gate oxide thickness may be derived from silicon carbide-based wide-bandgap materials utilizing linear and polynomial approaches using thermal oxidation durations at different temperatures for high-power applications. The regression models and formulations produced in this work are expected to aid the researchers in determining appropriate oxide thickness under practicable process conditions, with the exception of real thermal oxidation process conditions. Hence, the outcome of this work is expected to save the processing time, material, and cost of the power semiconductor device fabrication technology, mainly for high voltage applications.
  • Publication
    Rectification performance of self-switching diode in various geometries using ATLAS simulator
    (IEEE, 2017-01-03)
    Nor Farhani Zakaria
    ;
    Shahrir Rizal Kasjoo
    ;
    Zarimawaty Zailan
    ;
    Muammar Mohamad Isa
    ;
    Mohd Khairuddin Md Arshad
    ;
    Sanna Taking
    Characterization on a planar nano-device, known as self-switching diode (SSD) aimed for rectification application at high frequencies is reported. Simulation has been conducted on InGaAs-based SSD with 70 nm L-shaped channels using twodimensional (2D) ATLAS simulator. The current-voltage (I-V) characteristic of the device is found asymmetrical, similar to I-V behavior of a diode. The structure geometries of the channel are varied in term of channel length, channel width, and trenches width to observe the I-V behavior of the device. Furthermore, the curvature co-efficient of the SSD has been evaluated by extrapolating the simulated I-V graphs and the rectification performance of each configuration has been observed and concluded. The results obtained can assist the optimization in the design of the SSD to efficiently operate as microwave rectifier, especially in radio frequency harvesting application.
      3