Papers by Author: Kamarulazizi Ibrahim

Abstract: This study involves synthesizing of nanostructured tin sulphide (SnS) thin film on a glass substrate by chemical bath deposition technique. SnS film was prepared using non-toxic trisodium citrate (TSC) as a complex agent. The structural and morphological characteristics of the film were characterized by using X-ray diffraction (XRD), optical field emission scanning electron microscopy (FESEM). The XRD pattern confirmed an orthorhombic structure. The FESEM image revealed nanoflakes of the as-prepared SnS thin film. Moreover, near-infrared (NIR) metal semiconductor metal photodetector, which exhibited good photoresponse characteristics under (750 nm) light illumination was fabricated. The photoresponse characteristics also were investigated at different illumination power densities. The photodetector revealed excellent reproducibility and stability characteristics.

Abstract: The influence of graphite grinding time on the formation of carbon nanotubes (CNTs), is investigated. Graphite with different grinding time is used for the growth of CNTs by a cost-effective method using a microwave oven. The samples produced using the different grinding time contain nanotubes with an average diameter in the range 31–50 nm as observed by field emission scanning electron microscopy (FESEM). The lowest intensity ratio of D and G bands (ID/IG) and full width at half maximum of G as identified by Raman spectroscopy for grinding time 20 minute indicates the improved crystallinity of CNTs.

Abstract: In this work, a comparative study using atomic force microscopy (AFM) and field emission–scanning electron microscopy (FESEM) has been carried out to assess the morphology of single cell Escherichia coli bacteria (E-coli). E-coli bacteria are a major concern for public health. Attention was focused on the certain strains of E-coli bacteria, because some strains can be toxic and cause food poisoning. The E-coli bacteria have attracted much research interest because this bacterium is easily to get, cheap and rapid reproductively. Imaging of E-coli recently, was improved by using high resolution microscopy. Current techniques for detection such as, AFM and FESEM has attracted great interest and emerging as a potentially powerful whole-organism fingerprinting tool for the rapid identification of bacteria. The obtained results of AFM and FESEM techniques have been compared to show the image quality of single cell E-coli.

Abstract: In this work, the influences of plasma pre-treatment on polyethylene terephthalate (PET) substrate to the properties of ZnO thin film have been carried out. ZnO thin films were successfully grown on PET substrate by spin coating method. In order to study the effects of plasma pre-treatment, a comparison of treated and untreated condition was employed. Water contact angle measurement had been carried out for PET wettability study prior to ZnO thin film coating. Morphology study of ZnO thin film was performed by scanning probe microscope (SPM). Besides, optical study of the ZnO thin film was done by using UV-vis spectrophotometer. All the measured results show that plasma pre-treatment of PET substrate plays an important role in enhancing the wettability of PET and optical properties of the ZnO thin films. In conclusion, pre-treatment of PET surface is essential to produce higher quality ZnO thin film on this particular substrate in which would pave the way for the integration of future devices.

Abstract: The nanofiber optic evanescent field sensor based on a changed cladding part as a sensor presented numerically. The influences of numerical opening, core radius of the fiber, the wavelength is effected on the light source and the submicron fiber on the sensors are promise to studied in this work. The results pointed out the sensitivity of the sensor increases when the numerical opening of the fiber is increases and the core radius is decreases. The NA of the fiber affects the sensitivity of the sensor. In the uniform core fiber, the increase in the NA increases the sensitivity of the sensor. Therefore, one should choose a fiber with high NA for the design of an evanescent-wave-absorption sensor if the core of the sensing segment uniform in diameter, so that the increase in the penetration depth or number of ray reflections or both, increases the evanescent absorption field and hence the sensitivity of the sensors. Keywords: fiber optic sensor, chemical sensors, biosensors, nanofiber optic.

Abstract: Aluminium (Al) thin films on polyimide (PI) plastic substrates prepared via thermal evaporation technique and annealed in nitrogen (N₂) ambient at different temperatures (250 - 400°C, for 30 minutes) have been investigated. Structural properties of the as-evaporated film have been studied by high resolution X-ray diffraction (HR-XRD). The result illustrates crystalline nature of the Al thin film with a dominant Al (111) peak at 2θ = 38.4°. Atomic force microscope (AFM) shows increased surface roughness root mean square (RMS) with increased annealing temperature (with roughness of 11.96 nm at 400°C). Sheet resistance drops with increased temperature and records the lowest reading (64 mΩ/) at 400°C. Besides, increased annealing temperature also results in reduced surface reflectance (with minimum reflectance of 73% reflectance in the visible region at 400°C). The effects of the resulting Al back contact properties towards thin film silicon (Si) solar cells on PI substrates were subsequently discussed.

Abstract: Sb layered Te/Cd thin films have been prepared by using Stacked Elemental Layer (SEL) method. The presence of mixed phases (CdTe and Sb2Te3) in the films was confirmed by the x-ray diffraction technique. The calculated structural parameters demonstrated the feasibility of Sb doping via SEL method. The topographical and electrical studies of the synthesized thin films depicted the influence of Sb on both surface morphology and conductivity. The values of conductivity of the annealed films were in between 2 x 10-3 and 175 x 10-2 Scm-2. A desired chemical composition of films was confirmed from spectrum shape analysis using energy dispersive x-ray.

Abstract: This work reported the fabrication of nanopits array pattern using electron beam lithography (EBL). The effects of electron dosage on pattern shape were evaluated through EBL with a positive resist, Poly Methyl Meth Acrylate (PMMA), under acceleration voltages of 20 and 30 kV. Pattern of nanopits with 200 nm diameter have been created on PMMA to investigate the effect of various electron beam doses. The SEM images have shown effect of the voltage and dosage variation on them. In addition, Monte Carlo simulation has been done to show the scattering of electrons and proximity effect at different voltages in PMMA in order to explain the experimental results.

Abstract: In this work, different thicknesses of silver (Ag) thin films were prepared on flexible polyethylene terephthalate (PET) plastic substrates by screen printing technology. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize morphology and surface roughness of the Ag thin films. Crystallinity and crystallites sizes of the films were verified on High resolution X-ray diffraction (HR-XRD) system. From the AFM, rough surfaces were revealed with root mean square surface roughness (RMS) ranging from 20 to 40 nm for different thicknesses of the films and were found to be strongly dependent on the film thickness. The HR-XRD spectra showed different crystalline orientations of Ag thin films (with various thicknesses) produced by the screen printing technique. All the experimental findings were subsequently discussed.

Abstract: This paper presents an analysis of diamond-like carbon thin film deposited using homebuilt microwave chemical vapor deposition. Two different deposition conditions were investigated, namely, with and without microwave power. Post deposition analysis included Raman spectroscopy, scanning electron microscope (SEM), energy dispersed X-ray (EDX), four-pointprobe resistivity measurements and refractive spectroscopy. Substrate with pretreatment was observed to have thin film formation. Samples with diamond paste pretreatment show better quality compared to SiC treated samples as suggested by Raman spectral. The presences of sp3 and sp2 peaks were identified in the Raman spectral. The overall resistivity is low due to the graphite content.