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 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 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...
ABSTRACT Chalcogenide phase change memory is a potential replacement to flash memory due to excellent properties such as high storage density, rapid phase transition and archival stability. Phase change non-volatile semiconductor memory technology is based on an electrically initiated, reversible rapid amorphous-to-crystalline phase change process in multicomponent chalcogenide alloy materials similar to those used in rewritable optical disks. For over a decade Ge2Sb2Te5 (GST) compound has be...
ABSTRACT Solar energy which is a free and abundant form of energy has the potential to provide sufficient power to the growing number of industries and population especially in the developing world. Its maximum exploitation has however been hindered by the high cost of silicon based solar cells which currently dominate the market. It has been reported that copper based thin film solar cell technology is known to be 40% cheaper than silicon based solar cells. In order to effectively exploit s...
ABSTRACT Energy crisis occasioned by a decline in the availability of fossil fuels and increasing carbon dioxide emissions that are causing global warming has enhanced interest in the development of clean and renewable sources of energy. Solar energy has a great potential of meeting a large fraction of energy needs using photovoltaics. While most PV cells in use today are Silicon-based, cells of other semiconductor materials have been manufactured. Considerable research has been focused in se...