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...
Abstract In this research an n-type CdxZn1-xS and p-type PbS thin films were optimised for solar cell applications employing chemical bath deposition technique. The thin films were prepared using thiourea and nitrates of cadmium, zinc and lead. Deposition of optimised CdxZn1-xS was done by CBD at 820 C and in alkaline conditions while that of PbS was done at room temperature and both films at normal atmospheric pressure utilizing aqueous conditions. This study concentrated on optimising...
ABSTRACT The purpose of this project was to design and develop a Computer Based Testing (CBT) system in order to facilitate the process of conducting e-examinations especially in tertiary institutions. There is a growing need to find an easy and effective way to carryout continuous assessments for the increasing population of students. The CBT system will afford instructors the opportunity to assign different weights to the multiple choice questions. The method adopted was a client/server ba...
Abstract Consumers’ complaints of estimated bills from the Utility have risen to an alarming extent in recent years. On the other hand, Utility incurs huge losses attributing it to electric energy consumption theft among consumers. These complaints by the utility and the consumer led to the quest for a system that in addition to recording energy consumption data, will be able to compute and report the data to the Utility remotely. This work proposes the implementation of smart meter which ...
ABSTRACT This project work covers the design and construction of a robotic arm mechanically capable of 5 Degrees of Freedom. It solves the problem of automatically detecting and picking up objects placed within distances of 10-30cm round the robot base platform. It does this by using a simplified forward and inverse kinematic relation modeled in two dimensional robot workspace. The work does not cover the more general case, of an n-linked (n>2) robotic arm working within a three dimensional ...
ABSTRACT This project presents a 40A maximum power point tracking solar charge controller. The MPPT charge controller tries to keep the voltage and the power stable. The MPPT charge controller will harvest more power from the solar array – it will adjust its input voltage to harvest the maximum power from the solar array and then transform this power to supply the varying voltage requirement of the battery plus load. An MPPT charge controller is an electronic DC to DC converter that optimi...
ABSTRACT The problem of epileptic power supply and its consequences in the developing countries is a generally known issue. Worst still, the hope that it will be addressed with the deregulation of electricity Industries in recent time are being dashed by flight to top class investors due to its poor implementation. There is a need to provide multiple sources of power and automatic mechanisms for switching from one source to another. This is achieved in this work where quadruple power supply ...
ABSTRACT A highly structured TiO2/In(OH)xSy/SnS solar cell has been developed based on the Extremely Thin Absorber (ETA) concept. In this set up, TiO2 formed the window layer, In(OH)xSy was used as a buffer layer while SnS was used as the thin absorber film. Its small band gap (~1.3eV) makes it more appropriate for optical absorption. Titanium Dioxide (TiO2) thin films was prepared by spray pyrolysis. Deposition time for TiO2 films varied in the range of 1-4 minutes that gave film thickness o...
ABSTRACT This work evaluated the path losses and strength of received signals of a 3G Network operating at frequency of 2.1GHz in Owerri metropolis using Drive test. There were serious cases of call drops and low Quality of signal (QoS) experienced within some part of the Owerri metropolis. This situation has been burdensome on the side of the network users, as that has made them incur a lot of financial losses and passed through pains. The network providers, on their side, also passed throu...
ABSTRACT Robot becomes widely used in industries due to their characteristics. Robot is able to work in 24 hours continuously without feeling tired unlike human that confine to certain time. The cost to setup the robot nowadays becomes more affordable and their long term prospect is bright judging from their capacity to perform. But in reality, there is no robot able to function perfectly and without making errors. A better controller is needed, to allow the robot performs efficiently and mak...