Publications Archives – Institute of Nano Electronic Engineering

Comparative Analysis on Aluminium Interdigitated Electrode Surface: Influence of Ionic Strength and Electrolytes Changes

December 5, 2024 By Editor

Abstract – The field of generating surface thin films in sensing applications is emerging, and the incorporation of thin film technology into sensor development for enhanced sensing is becoming increasingly significant in various industries such as healthcare, environmental monitoring, and food safety. However, in order to achieve higher specificity in biosensing, advances in nanomaterial biofunctionalization are crucial. This research focuses on the fabrication and characterization of nanobiosensors with surface modification using two different sensing materials: zinc oxide and gold nanorod nanocomposites. The aim of this study was to enhance the sensing capabilities of nanobiosensors by incorporating surface modification with different sensing materials. The fabrication of nanobiosensors involved using silicon as the base material and conventional photolithography to fabricate aluminium interdigitated electrodes with three different structures and gap sizes. AutoCAD software was utilized to create three different photo masks with varying gap sizes. Physical characterization of the fabricated ALIDEs was conducted using atomic force microscope, high power microscope, scanning electron microscope, and 3D-profilormeter. The electrical characterization of the ALIDEs was performed using a Keithley 6487 picoammeter. I-V measurements were conducted on bare ALIDEs as well as surface modified ALIDEs with zinc oxide and gold nanorod. I-V measurements were also performed for pH scouting. The I-V measurements on bare ALIDEs revealed that ALIDEs modified with gold nanorod conducted the least current compared to ALIDEs modified with zinc oxide. Furthermore, the ALIDEs modified with gold nanorod were found to be stable under various electrolytes environments after undergoing pH scouting.

Corresponding Author: Prof. Dr. Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

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Link to Publication: https://doi.org/10.58915/ijneam.v17iJune.8 30

Chitosan-mediated tailoring of cadmium sulphide nanoparticle: Synthesis, properties, and interactive mechanisms

June 10, 2024 By Editor

Abstract – This study explores the synergistic effects of chitosan-coated cadmium sulphide (CdS) nanoparticles (NPs) at varying concentrations on their structural, optical, and photocatalytic properties. CdS NPs are known for their promising photocatalytic potential, but their practical application often requires stability enhancement and reduced toxicity. Chitosan, a natural biopolymer, offers unique advantages such as biocompatibility and heavy metal adsorption capabilities, making it an attractive candidate for surface modification of CdS NPs. Our investigation reveals that chitosan-coated CdS NPs exhibit concentration-dependent changes in their crystalline structure, bandgap energy, particle size, and vibrational characteristics. Notably, CdS NPs synthesized with 1.5 g chitosan concentration display the smallest bandgap and particle size, suggesting optimal photocatalytic activity. This research provides valuable insights into tailoring CdS NPs for efficient visible light photocatalysis, with implications in environmental remediation and energy conversion.

Corresponding Author: Prof. Dr. Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

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Link to Publication: https://doi.org/10.1016/j.procbio.2024.05.01 4

Numerical Simulation on the Impact of Back Gate Voltage in Thin Body and Thin Buried Oxide of Silicon on Insulator (SOI) MOSFETs

December 1, 2023 By Editor

Abstract – Silicon-on-Insulator (SOI) technology provides a solution for controlling Short-Channel Effects (SCEs) and enhancing the performance of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). However, scaling down SOI MOSFETs to a nanometer scale does not necessarily yield further scaling benefits. Introducing multiple gates, such as a double gate configuration, can effectively mitigate SCEs. Nonetheless, fabricating a flawless double gate structure is an exceedingly challenging endeavor that remains unrealized. The adoption of a back gate bias, with an asymmetrical thickness arrangement between the front and back gates, mimicking the behavior of a double gate, offers an alternative approach. This approach has the potential to modify the electrical characteristics of the device, thus potentially leading to improved control over SCEs. In this study, we employed 2D simulations using Atlas to investigate the influence of back gate biases, namely, -2.0 V, 0 V, and 2.0 V on a 10 nm silicon thickness at the top and a 20 nm buried oxide thickness for n-channel MOSFETs. We focused on key parameters, including threshold voltage (VTh), Drain Induced Barrier Lowering (DIBL), and Subthreshold Swing (SS). The results demonstrate that a negative back gate bias is the most favorable configuration, as it yields superior performance. This translates into more effectively controlled SCEs across all the parameters of interest.

Corresponding Author: Dr. Mohamad Faris Mohamad Fathil
Corresponding Author’s Email: mohamadfaris@unimap.edu.my

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Link to Publication: https://ijneam.unimap.edu.my/index.php/vol-16-no-4-october-2023

A gold nanoparticles coated unclad single mode fiber-optic sensor based on localized surface plasmon resonance

June 10, 2023 By Editor

Abstract – In the last few decays, the fiber-optic was employed in the field of sensing because of its benefits in contrast to other types of sensors such as small size, easy to fabricate, high response, and flexibility. In this study, unclad single mode fiber-optic sensor is proposed to operate at 650 nm wavelength. COMSOL Multiphysics 5.1 finite element method (FEM) is used to design the sensor and tested it theoretically. The middle portion of the fiber cladding is removed and replaced by gold nanoparticles (Au NPs) of 50 nm thickness. Analytic layer of 3 μm thickness was immersed in different liquids in range of refractive index (RI) from 1.000281 to 1.39. These liquids are NaCl Deionized (DI) water solution, sucrose-Deionized (DI) water solution, and glycerol solution Deionized (DI) water. It was found that the highest obtained sensitivity and resolution are for glycerol-DI water solution with value of 3157.98 (nm/RIU) and 3.16 × 10–5 (RIU), respectively. Furthermore, it is easy to fabricate and of low cost. In experiments, pulsed laser ablation (PLA) was used to prepare Au NPs. X-ray diffraction (XRD) shown that the peak of the intensity grew as the ablated energy increased as well as the structure crystallization. Transmission electron microscopy (TEM) revealed an average diameter of 30 nm at the three ablated energies, while X-ray spectroscopy (EDX) spectrum has indicated the presence of Au NPs in the prepared solution. The photoluminescence (PL) and ultraviolet–visible UV–Vis transmission were used to study the optical properties of the prepared Au NPs. An optical spectrum analyzer was used to obtain the sensor’s output results. It has shown that best intensity was obtained for sucrose which confined with theoretical results.

Corresponding Author: Prof. Dr. Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

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Link to Publication: https://doi.org/10.1038/s41598-023-32852-6

Faradaic electrochemical impedimetric analysis on MoS2/Au-NPs decorated surface for C-reactive protein detection

December 7, 2022 By Editor

Abstract – Background: A label-free Faradaic electrochemical impedimetric was developed for a highly sensitive detection of C-reactive protein using a gold interdigitated microelectrode bio-sensing platform enhanced by a gold nanoparticle-decorated molybdenum disulfide (Au-NPs/MoS2) nanosheet via selected chemical linking processes. C-reactive protein (C-RP), a crystalline protein, generates by the liver and hikes when there is inflammation throughout the patients’ body. The concentrations of C-RP plasma levels tend to increase rapidly when the patient facing major injury which will lead to cardiovascular disease (CVD). Methods: The 5 µm microelectrode and gap size g-IDE with the nanostructured materials was demonstrated to increase the impedimetric detection response in Faradaic-mode electrochemical impedance spectroscopy high performance detection environment. The high surface area-to-volume ratio of the modified Au-NPs/MoS2 nanocomposite increased the probes loading onto the transducer and enhanced the impedimetric detection response of the C-RP target post-binding due to an amplified net change in the charge transfer resistance. The developed immunoassay revealed a linear detection of C-RP biomarker in a logarithmic-scale from as low as 1 fg/mL up to 1 µg/mL, and a limit of detection of 0.01 fg/mL. The sensor shows great potential as an early warning risk for cardiovascular disease at a threshold concentration value of C-RP at 1 µg/mL. Significant findings: The biosensor demonstrates an excellent discrimination against other competing proteins in serum, exhibiting the highest predilection to C-RP spiked human serum target. The sensor’s reproducibility is reported within an acceptable range of relative standard deviation of 1–4% for n = 3.

Corresponding Author: Assoc. Prof. Ir. Dr. Mohd Khairuddin Md Arshad
Corresponding Author’s Email: mohd.khairuddin@unimap.edu.my

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Link to Publication: https://doi.org/10.1016/j.jtice.2022.104450