Nurjuliana Juhari
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Preferred name
Nurjuliana Juhari
Official Name
Nurjuliana, Juhari
Alternative Name
Juhari, Nurjuliana Binti
Juhari, Nurjuliana
Juhari, N.
Juhari, N. J.
Main Affiliation
Scopus Author ID
22634152000
Researcher ID
CWQ-4839-2022

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Analysis of power distribution in mach zehnder interferometer polymer-based waveguide for sensing applications

2022-12 , Mohd. Azarulsani Md. Azidin , Nurjuliana Juhari , Arif Mawardi Ismail , Norhayati Sabani

Two Mach Zehnder Interferometer (MZI) polymer-based waveguide designs namely MZI symmetrical and MZI asymmetrical structures were simulated and analyzed using Optiwave OptiBPM10. The two designs with device size of 4000μm x 300μm exhibit clear optical propagation path when light is simulated through them as well as displaying single mode profile. Highest output power was obtained by the MZI symmetrical design at 0.90 a.u, which suggests better waveguide design for sensing applications.

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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.

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Design of arrayed waveguide grating (AWG) demultiplexer based PMMA for narrow channel spacing

2020-01-08 , Nurjuliana Juhari , Yusof, Muhammad Fadzliazuan , Mohamad Halim Abd. Wahid , Nur Syakimah Ismail

Arrayed Waveguide Grating (AWG) based PMMA polymer that functioning as multiplexer/demultiplexer (mux/de-mux) having good potential in WDM system and interferometer optical sensor. Besides, AWG is suitable for larger count optical signals and good filter response devices. AWG demultiplexer based polymer was simulated using Beam Propagation Method (BPM) under TE mode with 1550 nm central wavelength. This work explores the performance of polymer-based AWG with straight waveguide structure that capable to produce 16-channels AWG device for 100 GHz (0.8 nm) channel spacing. The 16-channels AWG based polymer produces low insertion loss of 3.430 dB and low crosstalk of -24.763 dB. The central wavelength for each output port gives almost similar values with the standard ITU-T DWDM wavelength grid with the smallest difference of 0.5 nm. This proposed device also capable to solve the demand on higher channel capacity especially to support internet usage and the needs of the best communication system.

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Electrochemical detection of heavy metal ions using gold nanoparticles on carbon dots extracted from curry leaves

2024-06 , Nur Syakimah Ismail , Aidil Safiy Kamarul Ariffin , Nurul Izzati Akmal Mohd Azman , Nur Hamidah Abdul Halim , Norhayati Sabani , Nurjuliana Juhari , Siti Aisyah Shamsudin

Carbon dots (CDs) have attracted attention due to their versatility in electronic and optical properties based on precursor and type of synthesis process. Recently, many researchers have focused on using natural resources or wastes to form CDs. Four samples of CDs have been synthesized from curry leaves using a microwave-assisted approach at heating powers of 700 and 800 V with durations of 5 and 8 minutes. UV-Vis and FTIR spectra reveal the existence of carbon graphitic elements with carboxyl and hydroxyl functional groups on the surfaces of CDs. CVs of AuNPs/CDs/GS electrodes in ferricyanide disclosed that as-synthesized CDs produced using a lower heating power of 700 W exhibit pronounced electrocatalytic activity with sluggish electron transfer kinetics. Conversely, as-synthesized CDs created with a higher heating power of 800 W demonstrate reduced electrocatalytic activity but rapid electron transfer kinetics. Electrochemical detection of Pb2+ ions was observed through a sharp peak around -0.42 to -0.438 V, while detection of Hg2+ ions was observed through two anodic peaks around +0.334 to +0.408 V during a forward scan in acetate buffer (pH 4.5) on AuNPs/CDs/GS electrodes when tested individually. These distinct peaks also appeared in mixture solutions, with a slight reduction in peak current density that suggests the selectivity of the AuNPs/CDs/GS electrodes towards Pb2+ and Hg2+ ion detection. The optimum AuNPs/CDs/GS electrode for sensitive and selective detection of Pb2+ and Hg2+ was recorded using CDs D as a functional supporting matrix for AuNPs that was synthesized using a heating power of 800 W for 8 minutes.

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Analysis of an electrically induced optical waveguide in a c-axis barium titanate thin film

2021-12 , Arif Mawardi Ismail , Prabakaran A/L Poopalan , Nurjuliana Juhari , Mohd. Azarulsani Md. Azidin

In this paper, we report our analysis of an electrically generated optical waveguide in a 𝑐- axis barium titanate (BTO) thin film. The waveguide consists of a BTO thin film which is sandwiched between two electrodes. The thin film forms a waveguide when a voltage difference is applied across the electrodes. It is found that the formed waveguide supports both TE and TM modes, with TM modes more tightly confined within the waveguide than TE modes. The possibility to turn the waveguide on and off simply by turning the electric field on and off may prove useful for optical switching.

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Electrochemiluminescence of carbon dots and nitrogen-doped carbon dots from a microwave-assisted method

2023-10 , Nurul Izzati Akmal Mohd Azman , Muhammad Amirul Afiq Abdul Halim , Nur Syakimah Ismail , Nur Hamidah Abdul Halim , Nurjuliana Juhari , Norhayati Sabani , Siti Aisyah Shamsudin , Eiichi Tamiya

This research focuses on the use of carbon dots (CDs) and nitrogen-doped carbon dots (NCDs) synthesized using a microwave-assisted method as electrochemiluminescence (ECL) luminophores. CDs have been synthesized using citric acid, while various concentrations of nitrogen-doped CDs have been successfully obtained by varying the amount of urea from 1 to 3 g with citric acid to produce NCD1, NCD,2 and NCD3. The ECL mechanism of CDs and NCDs on screen-printed electrodes has been studied using cyclic voltammetry (CV). ECL emission from as-prepared CDs and NCDs was observed in PBS with potassium persulfate (K2S2O8) as a co-reactant. The addition of potassium chloride (KCl) as a supporting electrolyte displays fast electroreduction of CDs and K2S2O8 to expedite the generation of CDs and peroxydisulfate radicals that simultaneously increase ECL intensity. Furthermore, as the concentration of nitrogen-doped CDs increases, so does the intensity of the ECL. NCD3 shows the highest ECL intensity by an increment of 86.4% in comparison to CDs in PBS with the addition of K2S2O8 and KCl. Finally, optimization of ECL measurement was carried out in terms of CV potential range, concentration of luminophore, supporting electrolyte, and co-reactant using NCD3 luminophore. The CV potential range at 0 to -2 V shows 50 mV of early CV reverse onset potential that resulted in an increase of 52.9% ECL intensity. Meanwhile, 30x dilution of NCD3, 0.1 M of supporting electrolyte KCl, and 0.1 M of co-reactant K2S2O8 show the optimum value to obtain high ECL intensity.

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Effect of heating power towards synthesis of carbon dots through microwave pyrolysis method for optical-based biosensor

2020-01-08 , Nur Syakimah Ismail , Husain, Umi Shahirah , Selvan S. , Mordani, Nor Afnia , Nurjuliana Juhari , Nur Hamidah Abdul Halim

This study focuses on the effect of heating power in producing carbon dots (CDs) using microwave-assisted pyrolysis from glucose and PEG-200. Glucose is one type of saccharide that contains carbon atom in their structure while PEG-200 is a polymer that acts as a stabilizer. Synthesis of CDs was carried out by using a domestic microwave at different heating power ranging from 300 to 600 Watts. Produced CDs were subjected to dilution, filtering and dialysis procedure for purification purpose. UV-Vis was carried out using PerkinElmer Lambda 35 Spectrophotometer to prove the present of carbon dots in the sample solution. Photoluminescence intensity was observed using Horiba FluoroLog Spectrophotometer together with Horiba iHR550 Imaging Spectrometer to show the emission wavelength and the emission color of CDs prepared. UV-Vis results show the present of CDs in each sample from absorption peaks in the range between 240 nm until 260 nm. The photoluminescence testing shows the emission wavelength of prepared CDs solution is around 430 nm to 570 nm which represent emission color of green-yellow luminescence. From this experiment, CDs that were prepared using a heating power of 450 Watt in 2 minutes and went through the filtering process produce the best luminescence properties. Prepared CDs display electrochemiluminescence (ECL) properties in the presence of co-reactant potassium peroxydisulfate using cyclic voltammetry to pave the way for optical-based biosensor application.

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An overview of semiconductor rectifier operating in the millimeter wave and terahertz region

2020-01-08 , Mohd Mokhar, Mohd Bazli , Shahrir Rizal Kasjoo , Nurjuliana Juhari , Nor Farhani Zakaria

An imaging system operated at millimeter (MM) waves and terahertz (THz) frequencies can be used in many applications such as safety monitoring, public security, medical, healthcare and manufacturing. Typically, these systems utilize rectifying antenna (rectenna) to convert electromagnetic radiation into usable DC power which will be used to generate images. One of the main components of rectenna is the rectifier. Hence, this paper explores the current review on several semiconductor rectifiers that have been significantly deployed for MM-wave/THz imaging systems. This includes Schottky diodes, metal-insulator-metal (MIM) diodes, self-switching diodes (SSDs) and ballistic rectifiers (BRs). The rectifying performance of these devices are discussed in terms of their voltage responsivity and noise-equivalent power (NEP). The standard fabrication process of each device is also presented in this paper as well as their recent development and achievement as high-frequency rectifiers for MM-wave/THz imaging systems.

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Characterization of all-optical Tofolli and Peres gates employing optimized SOA-NOLM

2020-01-08 , Nur Hafizah Ghazali , Mohamad Halim Abd. Wahid , Nor Azura Malini Ahmad Hambali , Nurjuliana Juhari , Zahari S.M. , Shahimin M.M.

In this work, all-optical reversible gates namely Tofolli and Peres are studied and characterized. The gates utilize semiconductor optical amplifier (SOA) in nonlinear loop optical mirror (NOLM). The reversible gates are performed at data rate 10 Gb/s with narrow Gaussian pulses as input signals. Delay of 130 ps and injection current of 170 mA have displayed the optimum outputs in the SOA-NOLM. Extinction ratio is greatly reduced, thus less noise interferes the logic operation in this simple technique. It is observed that Peres gate has shown a higher output power compare to Toffoli gate. This could be due to multiple amplification that are experienced by the signals. Other than the gain, injection current and delay are shown to give major effect in producing the correct bits at the outputs. The SOA-NOLM also can be cascaded for other arithmetic signal processing operation at high frequency. It is also recorded that the design consumes low power especially in small signal gain process. Thus, the design indicates its versatility to be executed in photonic integrated circuits for ultrafast signal control through fiber networks.

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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.

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