ABSTRACT Indium Selenide (InxSey) has shown great advantages over the conventionally used Ge2Sb2Te5 as a phase change memory material (PCM). It has been established that the electrical resistivity of Indium-Selenide based memory cell can be varied by a factor of 105 related with the degree of crystallization as compared with 103 for Ge2Sb2Te5. It is this wider change of electrical resistivity and higher electrical resistivity that has attracted great attention to Indium-Selenide based phase ...
ABSTRACT Thin films for solar cell application have been found to be unstable when used in extreme weather conditions. Therefore there is a quest for the study of effects on light soaking and exposure to outdoor conditions on SnxSey/ZnO:Sn solar cell. A p-n junction thin film solar cell was prepared using SnSe as the absorber layer and ZnO:Sn as a window layer. Tin selenide thin films were prepared at different ratios using pure tin pellets and selenium powder. The glass tube containing mixe...
ABSTRACT Various elements and compounds have been studied to fabricate thin film semiconductors for the solar cell applications. Apart from the materials used in the cell fabrication, the performance of solar cell also depends on the technique used and deposition parameters.In this research,the performance of the p-n junction solar cell is improved by depositing thin films at optimized deposition temperature. The optical and electrical behavior of thin films was analyzedundervariedchemical co...
As the future size of phase change random access memory is scaled down, its reliability in data retention, archival life and power consumption is often disturbed by problems such as elemental segregation and compositional variation caused by repetitive phase transformation. These phenomena are closely related to the crystallization kinetics under various environments. The crystallization kinetics at low temperature and slow transition rates of SnxSey thin films have been investigated usi...
Abstract Thin films of SnO2:Al and ZnO: Al were deposited under different deposition parameters. Effect of substrate temperature, Carrier gas pressure, substrate to nozzle distance and doping percentages were investigated to obtain optimum conditions for deposition of p-SnO2:Al for LED applications. Optimized film of SnO2:Al was deposited at temperature of 408 o C, nozzle substrate distance of 4.75 cm, carrier gas pressure of 1.88 bars and aluminium doping atomic percent of 5.37 %. Solid spec...
ABSTRACT The recent power sector reform in Nigeria has thrown up enormous challenges in this sector, ranging from the construction of more power stations, construction of new transmission lines and substations. The existing network of 8-plants and 26 bus-bars expanded to the proposed network of 16 generating plants with 49 bus-bars. This network expansion requires reappraisal for power evacuation capabilities, relay systems setting and establishment of stability margins for adverse system fa...
ABSTRACT This work analysed the current state of power system in Nigeria with emphasis on distribution system using Akwa Ibom Distribution System as a case study. The components of the study system were analyzed. This work adopted the analytical and simulation approach to reliability and stability assessment. Analysing the system the way it is shows that the system was not reliable and stable. The outcome gotten from the base state of the system confirmed this. The results for the current st...
ABSTRACT The basic idea deals with detecting the voltage collapse ahead of time to provide the operators a lead time for remedial actions and for possible prevention of blackouts. To detect cases of voltage collapse, pattern recognition in conjunction with power system simulator for engineering (PSSE) program was created and then deployed in Nigeria 330KV integrated power system to develop Regularized Least Squares Classification (RLSC) as well as Classification and Regression Trees (CART) h...
ABSTRACT The goal of this project was to design a data logging interface using wireless network principle in order to facilitate the process of monitoring physical parameters such as temperature, pressure, humidity, e.tc in the environment. There is a growing desire to find an efficient and cost effective means to monitor these physical parameters, especially at home and industries. The absence of a means to monitor these quantities in an environment has led to so many inadequacies. The meth...
ABSTRACT The word “vote” means to choose from a list, to elect or to determine. The main goal of voting (in a scenario involving the students of a given tertiary institution), is to come up with student-leaders of the students’ choice.Most tertiary institutions, FUTO not an exception have problems when it comes to voting. Some of the problems involved include rigging votes during election, insecure or inaccessible polling arena, inexperienced personnel and so on because voting in these...
Abstract Phase Change Memory is one of the most promising concepts for the future generations of Non Volatile Memories. Extensive work is nowadays performed on the Phase Change Materials to optimize the cell properties for specific applications. In particular, for the embedded memory market, it is desirable to reduce the writing current while raising data retention capability. In2Se3 has shown remarkable characteristics for phase change random access memory (PRAM) applications. Among the rema...
BSTRACT A solar cell is a device that converts light energy into electricity by photovoltaic effect. The photovoltaic effect refers to photons of light exciting electrons into a higher state of energy, allowing them to act as charge careers for an electric current. Materials presently used for solar cell fabrication include silicon, gallium arsenide (GaAs) among others. However, these materials are expensive and not readily available. As a result, there is need to search for alternative mater...
ABSTRACT The desire for smaller, more efficient and faster semiconductor devices has made the design of the Schottky devices, material preparation and characterization very vital. There is little research if any on the effect of Schottky contact geometry on I-V characteristics. In this study various circular and rectangular thin filmed Al/ZnSe Schottky diodes were designed by varying; the shape, area of the Schottky contact, the inter electrode distance and thickness of the thin film ZnSe. F...
ABSTRACT In this work, SnO2 thin films were deposited on a glass substrate by spray pyrolysis technique using aqueous solution of tin (IV) chloride (SnCl4.5H2O) dissolved in ethanol. Different types of thin films such as SnO2, F: SnO2, Pd: SnO2 and Pd-F: SnO2 were deposited at a substrate temperature of 450 0C. Post deposition treatment: annealing and passivation were performed in a tube furnace at 450 0C. The samples, both as prepared and treated, were thereafter characterized by optical and...
ABSTRACT Optical spectroscopy is a non-destructive and contactless method for characterizing optical and electrical properties of thin films; reflectance, transmittance, refractive index, permittivity and band gap. These properties determine the application of a thin film as a polarizer, laser, solar cell or photodiode among others. To measure accurately optical properties of thin films, the common types of optical spectrometers used are ellipsometers and spectrophotometers. However these ins...