Rf-Mbe Growth Of Iii-Nitrides Heterostructures For Light Detecting Applications

Dalam penyelidikan ini, GaN p-n struktur homo, AlN/GaN struktur hetero, dan AlxGa1-xN/GaN struktur hetero telah berjaya ditumbuhkan di atas substrat silikon (Si) (111) menerusi epitaksi alur molekul plasma terbantu (MBE) untuk aplikasi pengesan foto. Galium (7N) dan aluminium (6N5) dengan ketulenan yang tinggi telah digunakan dalam sel Knudsen dan nitrogen (7N) berketulenan tinggi telah dibekalkan kepada frekuensi radio (RF) 13.56 MHz untuk menjana sumber spesis nitrogen reaktif. Nilai tekanan nitrogen dan kuasa pelepasan masing-masing ditetapkan malar pada 1.5x10-5 Torr dan 300 W sepanjang projek ini. Morfologi permukaan, sifat-sifat struktur dan optik daripada semua sampel telah disiasat dengan menggunakan pantulan belauan elektron bertenaga tinggi (RHEED), mikroskop imbasan elektron (SEM), mikroskop imbasan electron pancaran medan (FESEM), mikroskop electron transmisi (TEM), mikroskop daya atom (AFM), belauan sinar-X beresolusi tinggi (XRD-HR), fotoluminesen (PL), dan spektroskopi Raman, masing-masing. In this research work, GaN p-n homostructures, AlN/GaN heterostructures, and AlxGa1-xN/Ga heterostructures were successfully grown on silicon (Si) (111) substrates by plasma-assisted molecular beam epitaxy (MBE) for photodetector applications. High purity gallium (7N) and aluminum (6N5) were used in the Knudsen cells and high purity nitrogen (7N) was supplied to 13.56 MHz radio frequency (RF) source to generate reactive nitrogen species. The nitrogen pressure and discharge power values were kept constant at 1.5x10-5 Torr and 300 W during this project, respectively. The surface morphology, structural and optical properties of all the samples were investigated by using reflection high energy electron diffraction (RHEED), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy, atomic force microscopy (AFM), high-resolution X-ray diffraction (HR-XRD), photoluminescence (PL), and Raman spectroscopy, respectively

Kesan Rawatan Kriogenik Terhadap Struktur Antaramuka Ni/Si Dalam Peranti Silikon Sebagai Pengesan Foto [QC373.P9 Z21 2008 f rb].

Projek ini mengkaji kesan rawatan kriogenik terhadap struktur antaramuka Ni/Si dalam silikon sebagai pengesan foto. This project studied the effects of cryogenic treatment on Ni/Si interface in silicon device as a photodetector

Path Optimization and Object Localization Using Hybrid Particle Swarm and Ant Colony Optimization for Mobile RFID Reader

This paper proposes a hybrid approach of Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO) for the mobile Radio Frequency Identification System (RFID) reader to get the shortest path for object localization. In this approach, we have adopted the ACO global pheromone updating information of ants to guide the update velocities and position for PSO based on nearest neighbor constraints. The pheromone information is used efficiently to guide the selection of each particle in a search space of its visits. The best path will be used for mobile RFID reader for objects localization in search space. Simulation results show that the method is effective, minimizing the number of visited nodes for a mobile RFID reader

Impact of service strategy on customer satisfaction of the rail management in Malaysia

This paper project is evaluates the level of customer satisfaction among the Malayan railways KTMB passengers. The factors with to evaluate the level of customer satisfaction are the on-line services, fare charging practices, customer services and advertisement.The dependent variable which measured is customer satisfaction. A quantitative approach with a multiple regression analysis was deployed to study the relationship between the independent variables and dependent variable. The factors such as the fare charging practices and customer services though show a positive relationship with customer satisfaction, but the relationship is not significant. However, the passengers are very concern about the on-line services, and advertisement used to communication with them to improve the on-line services, and advertisement in other deliver customer satisfaction continuously

Investigation of structural, optical and antibacterial activity of zinc oxide nanoparticles (ZnONPs)

Investigations of zinc oxide nanoparticles (ZnONPS) in various applications had been well-reported. In this study, the ZnONPs was synthesized using the simple method which is sol-gel method. Then, the structural and optical of ZnONPs under different pH value (pH7-11) were characterized. X-ray diffraction (XRD) measurements were performed to obtain the structural information of the samples. The XRD results showed that the ZnO has hexagonal wurtzite structure and dominated in plane (100), (002), and (101). To acquire the morphology and particle size of the samples, Field Emission Scanning Electron Microscopy (FESEM) was used plus the Energy Dispersive X-ray (EDX) to obtain the elemental composition of ZNONPs. Fourier Transform Infrared Spectroscopy (FTIR) was to determine the functional group of the samples. The Photoluminescence (PL) and Ultraviolet-Visible (UV-Vis) was employed to study the optical properties of the samples and the absorption peak of the samples under various pH value. While for the antibacterial activity, the ZnONPs under different pH value were tested against coliform bacteria. From the antibacterial activity, the higher pH value of ZnONPs shows the greater of inhibition zone. ZnONPs can be one of the alternative/potential of metal oxide nanoparticles for wastewater treatment since it has the antibacterial properties and partly neutral to water

Tensile behaviour for mercerization of single kenaf fiber

A natural fiber including kenaf fibers that reinforce with polymeric composite has increased attention in the manufacturing industries. However, the poor adhesion between fiber and matrix are commonly encountered respectively to their compatibility nature namely hydrophilic and hydrophobic. Therefore, alkaline treatment has introduced to reduce the hydrophilic effect of natural fiber. This paper presents the treatment of single kenaf fibers following tensile test and predicted using analysis of variance (ANOVA). Here, the kenaf fibers were modified using NaOH at different solutions. Then, the single kenaf fiber was performed under ASTM D3379-89 standard. The results showed that kenaf fiber which treats with NaOH solution of 6% significantly offered the outstanding performance of the tensile behaviour

Investigations of structural and optical properties of zinc oxide thin films growth on various substrates

In this research, the structural and optical properties of Zinc Oxide (ZnO) thin film were successfully deposited on various substrates including silicon (Si), sapphire (Al2O3), polyethylene terephthalate (PET) and polypropylene carbonate (PPC) by Radio Frequency (RF) sputtering technique. In this project, the structural and optical properties of the samples were studied by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Raman Spectroscopy, and Photoluminescence (PL). The XRD test revealed that the samples have a wurtzite structure as the peaks dominated by ZnO (0 0 2). AFM test found out that root mean square (rms) for thin film samples ranging from 1 to 8 nm. Raman spectra detected the existence of certain Raman-active modes inside the samples. In PL spectra, the peak emissions observed for all the ZnO thin film samples ranging around 376.05–381.5 nm, thus closer to the pure ZnO. Through the FESEM image, most of the samples except ZnO/PPC sample showed the granular surface morphology, while the ZnO/PPC sample revealed the hexagonal like shapes with uniform distribution. The results exhibited that the ZnO thin films grown on ZnO/PET have the best quality among all the samples

Recovery of lowland dipterocarp forests under the Malayan uniform system

Recovery assessment of the logged lowland dipterocarp forests based on phytosociological studies conducted in the state of Negeri Sembilan, Malaysia, showed that the recovery rate of the logged areas depends on the state and degree of harvesting carried out on the stands. The stands that were harvested from 1963 to 1973 under the Malayan Uniform System (MUS) have shown a relatively slow recovery rate. The sites have small average coverage by emergent (ST) trees, ranging from 8% to 14%, and only a few dipterocarps occupy this layer. On the other hand, the stands harvested in the 1950s have recovered towards their original state prior to harvest. The stands recorded an average ST-layer coverage of 24%, T1 layer (57%) and T2 layer (45%). The analysis of species composition recovery and species abundance showed similar trends, with F50 stands appearing similar to the primary forest. The study shows that it takes at least approximately 40 years for the logged-over stands under the MUS to recover to their original state

Influence of pH variations on zinc oxide nanoparticles and their antibacterial activity

Zinc oxide nanoparticles (ZnONPs) were synthesized by the sol-gel method at various pH values. XRD, FTIR, FESEM, UV–vis and PL were accomplished to characterize the structural, functional groups, morphology, and optical properties of the samples. The disk diffusion method was conducted to investigates the antibacterial properties of the ZnONPs. The particle sizes of the ZnONPs synthesized between pH 7-11 was explored vary from 59.56–46.45 nm and mostly in spherical shape. Ultraviolet-visible analysis (UV–vis) also revealed the optical properties with the optical band gap of 3.29, 3.31, 3.33, 3.31 and 3.29 eV correspond to ZnONPs in pH 7-11. While the highest PL spectra of ZnONPs display a blue emission band around 484 nm in the UV range at pH 9. The highest diameter of inhibition zone after 120 h was found at 4.4 ± 0.1 cm at pH 11 of ZnONPs. In this research, the average particles size of ZnONPs and the intensities of the XRD pattern decreases with the increasing pH values. However, with the increasing pH values, the antibacterial activity becomes effective