Tijjani Adam | Universiti Malaysia Perlis (UniMAP) (original) (raw)

Papers by Tijjani Adam

Journal of Physics: Conference Series, 2017

Because of the sizes and the capabilities, the Microfluidic devices has got the spectacular atten... more Because of the sizes and the capabilities, the Microfluidic devices has got the spectacular attention with a number of significant advantages. Microfluidics devices refer to a set of technologies that control the flow of liquids or gases typically measured in a miniaturized system. This review aims at summarizing three important components in Microfluidic devices that are Micromixer, Microchannel and Microchamber in fluid handling capabilities. Investigations in recent five years using Micromixer either using active or passive mechanisms of fluid manipulation for mixing will were elaborated. The Microchannel mixing either with laminar flow and turbulent flow experiment were also elaborated. Lastly, the applications of Microchamber as a component part in Microfluidic devices also reviewed.

Taguchi method was performed on a series of ultra thin SiO 2 films in order to study the paramete... more Taguchi method was performed on a series of ultra thin SiO 2 films in order to study the parameter affecting the oxide growth. The samples of ultra thin SiO 2 were prepared through a dry oxidation method using a high temperature furnace. There are three level of temperature used, that are 750, 800 and 850 0 C. The samples were grown in 0.333 litre/min, 0.667liter/min and 1liter/min oxygen flow rate and with variation in time, that is 1, 2 and 3 minutes. The thickness characterization was done by elipsometer. The thickness of the oxide was obtained and is ranging from 1 to 5 nm. All the data has been interpreted using Taguchi's method to analyze the most significant factors in producing an ultra thin silicon dioxide using a high temperature furnace.

In fabrication of Micro/ Nano structure, alignment and exposure are the most critical steps in ph... more In fabrication of Micro/ Nano structure, alignment and exposure are the most critical steps in photolithography process, the resolution requirements and precise alignment are vital; each mask needs to be precisely aligned with original alignment mark. Otherwise, it can't successfully transfer the original pattern to the wafer surface causing device and circuit failure and the photo resist must be very sensitive to the exposure light to achieve reasonable throughput and the standard thickness should be 1.2µm. 24 wafers are used in this study, the wafers are separated into 2 sets, and each set which consists of 12 wafers. The first set is coated, exposed and development and the second set is also exposed and developed after being coated. after the wafer went through the standard cleaning procedure, the wafers were then coated using standard recipes which the spin speed ranging from 6500 to 7600 rpm in 100 rpm incremental Subsequently, the photoresist thickness of each wafer is mea...

Taguchi method was performed on a series of ultra-thin Si 3 N 4 films in order to study the param... more Taguchi method was performed on a series of ultra-thin Si 3 N 4 films in order to study the parameter affecting the Nitride growth. The samples of ultrathin Si 3 N 4 were prepared through a dry nitridation/oxidation method using a high temperature furnace. There are three levels of temperature used, that are 750, 800 and 950 0 C. The samples were grown in 0.333 litre/min, 0.667liter/min and 1liter/min nitrogen flow rate and with variation in time that is 1, 2 and 3 minutes. The thickness characterization was done by elipsometer. The thickness of the nitride was obtained and is ranging from 1 to 5 nm. All the data were interpreted using Taguchi method to optimize the processer parameters to fabricate Si3N4 films. The most affecting factors in producing an ultra-thin silicon Nitride using a high temperature furnace.

A chip for label-free detection of single biomolecules was fabricated by means of “top-down” phot... more A chip for label-free detection of single biomolecules was fabricated by means of “top-down” photolithography. First, the device was designed with AutoCAD software. Three masks were created and subsequently transferred onto the commercial chrome mask. Standard CMOS photolithography coupled with ICP dry etching was used for fabrication of the silicon nanowires. The nanowires fabrication process includes three major steps: wire formation, wire trimming and gold pad formation. Next, the fluidic chamber was constructed in two main steps: master template development, and replica fabrication of chamber and inlet/outlet channel. After that, the fabricated devices were inspected and characterized with FESEM. After the devices were individually tested, they were integrated through a two-step plasma oxidation process: surface treatment and device mounting. Finally, silicon nanowire surface modification and DNA immobilization for DNA hybridization were performed on silicon nanowire Labon-Chip....

Micro mixer is an important component in biomedical application, because many bio-molecular proce... more Micro mixer is an important component in biomedical application, because many bio-molecular processes require rapid and complete mixing. Due to the small channel size of a micro fluidic system, the flow is usually laminar, and so the mixing of fluids in the system remains a challenge. Technologies that currently exist to address the technological aspects of point of care test development is microfluidic and this device have the potential and the toolset to make many POC diagnostic systems possible. Microfluidic transportation and effective mixing are of importance. Hence, the study demostrated an in-house fabrication and characterization of passive flow driven with low Reynolds number of 76 using capillary phenomena. The fabricated device was tested using two samples with different colours for uniform mixing. The uniform concentration of 3mole/g at 76% total length of the micromixer at a point where sensing elements are expected to be placed is obtained.

The Journal of Applied Sciences Research, 2012

The paper contain a report on proposal to use a single atom sensor for biological application, we... more The paper contain a report on proposal to use a single atom sensor for biological application, we are reporting a possibility of creating interatomic interaction between sensor and biological species through strong, fundamental and natural force of attraction that exist between the protons of the sensing element and ionic properties of biological species could be used as a source for introduction of natural binding chemistry of electrostatic attraction of the particles to bind biological species on a sensing element.

Computational Simulation of Surface Interaction between Organic and Inorganic has been studied by... more Computational Simulation of Surface Interaction between Organic and Inorganic has been studied by some researchers and much work has been done to elucidate the mechanisms involved in stabilizing the molecule on microstructure and nanostructure but unfortunately, the detailed binding chemistry is still unclear. The study here intended to tackle this problem and the simulation starts by designing the different model with different number of nanowire gold electrode in 3D dimension. Then, design also the model cross section interaction nanowire gold electrode to surface charge as DNA in 2D dimension. After the successful design, the models were simulated using COMSOL software. The electric potential and electric field response for the three models were measured and compared. The electric current will reduce when more number of the nanowire and the electric field will increase when more number of nanowire on gold electrode get in contact . Keywords— Gold electrode; simulation; organic; D...

At a macro scale level, mixing is generally achieved by a turbulent flow, which makes possible of... more At a macro scale level, mixing is generally achieved by a turbulent flow, which makes possible of segregating the fluid in small domains, thereby leading to an increase in the contact surface and decrease in the mixing path. At low Reynolds number, the viscous effects dominate inertial effects and a completely laminar flow occurs. In the laminar flow system, fluid streams flow parallel to each other and the velocity at any location within the fluid stream is variant with pressure when boundary conditions are constant and due to the change in surface area–to-volume tension and diffusion, do not simply scale linearly from large to small devices. This makes the use of microfluidic as a mixing device difficult. Thus, the study posed to bridge this gap by created geometrically enhanced Micromixer for homogenous mixing.

Scientific Reports, 2021

Arsenic is a major global threat to the ecosystem. Here we describe a highly accurate sensing pla... more Arsenic is a major global threat to the ecosystem. Here we describe a highly accurate sensing platform using silica nanoparticles/graphene at the surface of aluminum interdigitated electrodes (Al IDE), able to detect trace amounts of arsenic(III) in rice grain samples. The morphology and electrical properties of fabricated Al IDEs were characterized and standardized using AFM, and SEM with EDX analyses. Micrometer scale Al IDEs were fabricated with silicon, aluminum, and oxygen as primary elements. Validation of the bare Al IDE with electrolyte fouling was performed at different pH levels. The sensing surface was stable with no electrolyte fouling at pH 7. Each chemical modification step was monitored with current–volt measurement. The surface chemical bonds were characterized by fourier transform infrared spectroscopy (FTIR) and revealed different peaks when interacting with arsenic (1600–1000 cm−1). Both silica nanoparticles and graphene presented a sensitive limit of detection as...

The aim of this paper is to present an overview, simulation and modeling study to improve the per... more The aim of this paper is to present an overview, simulation and modeling study to improve the performance of Flash Memory (FM) devices such as programming speed and programming voltage. To improve the performing of FM device, the tunnel barrier thickness scaling is a major challenge. In current flash devices or conventional flash memory, single silicon oxide (SiO2) was obtained as a tunnel barrier and the thickness is approximately in the 5–10 nm range. Reducing the tunnel barrier below this range, will achieve low programming speed and high programming speed but the charge loss through also large. In order to achieve this research, the basic of semiconductor memory firstly was study include the programming tunneling mechanism and programming operation. Then the both structure techniques were simulated used TCAD software and lastly were model to calculate the electrical behavior like programming speed and programming voltage. The programming speed is calculated from the shift data o...

Applied Physics A, 2019

This study describes the fabrication of three different gap-fingered aluminum-interdigitated elec... more This study describes the fabrication of three different gap-fingered aluminum-interdigitated electrodes (AlIDEs) on the silicon substrate based on photolithographic method, followed by integration of the gold nanorod-zinc oxide nanocomposite. The IDE masks were designed using AutoCAD software with the gaps of 10, 20, and 30 μm for design 1, 2, and 3, respectively. The morphological and electrical characterizations were subsequently performed using 3D-nanoprofiler, atomic force microscopy, high-power microscopy (HPM), scanning electron microscopy (SEM), and I-V. Validation of the fabricated surfaces (AlIDEs with/without gold nanorod-zinc oxide nanocomposite) against the electrolytes was performed at different pHs which are ranging from 1 to 12. SEM revealed the following gaps, 18.4, 20, and 40.5 μm for bare 1, 2, and 3, respectively. The measurements on I-V for bare AlIDEs indicated the electrolyte influences at different pH solutions, which were almost similar in terms of current variations except at highly acidic and alkaline. AlIDEs were well fabricated and the smaller the gap displayed the better the sensitivity, hence device 1 AlIDE has a good performance. Using different pH solutions which ranging from pH 1-12, before and after AlIDEs were coated with zinc oxide and gold nanorod. The responses of the devices were similar, fluctuating from highly acidic region to highly alkaline region in the cases of AlIDEs bare 1 and 3. Bare 2 AlIDE displayed similar responses with the AlIDE that was deposited with gold nanorod. With these results, we can conclude that deposition of gold nanorod on the device brought about the orderly response to the different pH and with the increment from acidic to alkaline increases, the proportional changes with the current were noticed.

Process Biochemistry, 2019

The universal burden of Parkinson's disease (PD) has more than doubled over the past generation d... more The universal burden of Parkinson's disease (PD) has more than doubled over the past generation due to the increasing numbers of elderly individuals, with possible contributions from extended disease duration and environmental factors. PD affects the basal ganglia and the substantia nigra in deep parts of the brain. The nerve cells in the substantia nigra produce the neurotransmitter dopamine, which is responsible for the movement of the body. When PD affects the basal ganglia and the substantia nigra in the brain, there is abnormal neurotransmission in the body, leading to speech impairment, slowness of movement (bradykinesia), balance disorder, postural instability, tremor, and muscle rigidity. Even though the cause of this disease is still unknown, some studies revealed that α-synuclein is a major constituent of Lewy bodies, protein clumps that are the pathological hallmark of PD. Furthermore, different lines of research are under investigation with the involvement of other biological macromolecules, such as microRNA and DNA. Therefore, this paper reviews the current states and perspectives on PD, including its nature, features, and management, and the methods available to predict PD. The essence of this review is that PD requires more investigation and the development of suitable technologies to provide assistance to PD patients to improve their life.

IOP Conference Series: Materials Science and Engineering, 2018

In recent days, both raw and treated water being consumed by human and animal posed serious threa... more In recent days, both raw and treated water being consumed by human and animal posed serious threat to the consumer. Due to heavy industrialization water easily carries heavy metals that are harmful to consumers. Heavy metal is from metal or metalloid which found in environmental surroundings that has its potential toxicity. Most case, it is taken undetected due to absences of able sensor to detect it. Thus, this study posed to design and characterize nano interdigitated electrode (Nano-IDE) surface modified using Mercaptopropyltriethoxy silane (MPTES) to create binding chemistry for the enhancement of electrochemical activities that will allow specific and selective detection of arsenic ions in water. This result of the study has shown the potential of the proposed device.

The usage of thick silicon substrates is widespread in electronic industries todays, silicon is t... more The usage of thick silicon substrates is widespread in electronic industries todays, silicon is the most important material in the semiconductor industries due to its excellent electrical, mechanical and chemical properties. Due to it being inert at room temperature and having anisotropic properties (electrical, mechanical chemical), silicon plays an important role in micro-electro-mechanical systems (MEMS) application. However, atomic interaction becoming complicated as the number of electrons increases. Atomic interaction beyond the hydrogen atom is indeed complex but quite possible by Schrodinger equation. Therefore, combination of models to explain atomic interaction via density functional theory, Kohn Sham and generalized gradient approximation is proposed. It its expected that the SiNW will show band gap transition with the decreasing size and the band gap properties under inter atomic stress. With this, it is possible to determine the atomic structure of nanowire fundamental behavior. Thus, Based o...

AIP Conference Proceedings, 2017

The nano structure based on silicon can be surface modified to be used as label-free biosensors t... more The nano structure based on silicon can be surface modified to be used as label-free biosensors that allow real-time measurements. The silicon nanowire surface was functionalized using 3aminopropyltrimethoxysilane (APTES), which functions as a facilitator to immobilize biomolecules on the silicon nanowire surface. The process is simple, economical; this will pave the way for point-of-care applications. However, the surface modification and subsequent detection mechanism still not clear. Thus, study proposed step by step process of silicon nano surface modification and its possible in specific and selective target detection of Supra-genome 21 Mers Salmonella. The device captured the molecule with precisely; the approach took the advantages of strong binding chemistry created between APTES and biomolecule. The results indicated how modifications of the nanowires provide sensing capability with strong surface chemistries that can lead to specific and selective target detection.

Journal of the Association of Arab Universities for Basic and Applied Sciences, 2017

Systematic Evolution of Ligands by EXponential enrichment (SELEX) is the method to select the spe... more Systematic Evolution of Ligands by EXponential enrichment (SELEX) is the method to select the specific aptamer against a wide range of targets. For this process, the initial library usually has a length of random sequences from 25 and it reaches over 100 bases. The lengthy sequences have disadvantages such as difficult to prepare, less stable and expensive. It is wise to prefer shorter version of aptamer for a wide range of applications including drug delivery process. It is a common practice to shorten the full-length aptamer by mapping analyses and it is tedious. Here, we used a crawling method to shorten the aptamer by different sequential deletion of bases from both 5 0 and 3 0 ends, assisted by Mfold web server application. Two different kinds of aptamer with varied lengths (randomized region of 30 and 74 bases) were desired for this study, generated against Influenza A/Panama/2007/1999 (H3N2) and gD protein of Herpes Simplex Virus-1. It was found that shortening the aptamer length by crawling pattern is possible with the assistance of Mfold web server application. The obtained results resemble the shortened aptamer derived by mapping analyses. The proposed strategy is recommended to predict the shorter aptamer without involving any wet experimental section.

2014 5th International Conference on Intelligent Systems, Modelling and Simulation, 2014

The Surface Acoustic Wave (SAW) is one of sensor types that can be used in multifunction in the s... more The Surface Acoustic Wave (SAW) is one of sensor types that can be used in multifunction in the sensing field. Hence, the purpose of this project is to study and investigate the design of SAW device for biosensor application. Several parameters and design has been varied and proposed to investigate the effect to the SAW Biosensor performance. The parameter such as total SAW IDT fingers and Split IDT design has successfully designed using AutoCAD software and fabricated using conventional lithography method. The Aluminum IDT was fabricated on ZnO/Si piezoelectric substrate and show a good result in term of electrical characterization and frequency response. From result, the proposed design with many fingers can increase the center frequency response while the split design control the insertion loss. It shows that these designs are suitable to apply in the SAW biosensor application.