The Formation Of Solar Cell Using Semi-Conductor Material (PDF/DOC)
Solar cell in other words called photovoltaic cell is the cell that generates electricity when light falls on it. As the word implies, photo means light, while voltaic means electricity. By the series and parallel electrically connection of these cells, a useful level of voltage and current can be achieved. When light falls on these cells, a certain portion of it is absorbed within the semi-conductor materials (cells).
The energy of the absorbed light mobilizes the electrons. The inbuilt electric field in the cells which is as a result of the doping method in the cells i.e the existence of holes and electrons in the cells, then causes the electrons to flow in a certain direction which is current in ampere. And by placing a metal contact on the top bottom of the cells the current together with voltage is drawn which can be used externally.
This write-up explains how solar cell can be formed using semi-conductor, say silicon type of solar cell which has terminal voltage of about 0.6v.
The chapter one gives a brief overview of what a semi-conductor material is, its conductivity and how it forms a solar cell (introductory part).
Chapter two treats the literature review of the write-up. It gives the history of solar cell technology.
Chapter three treats the main body of the write-up it explains how photovoltaic modules are made to achieve a useful level of voltage and current, the characteristics of a semi-conductor and their doping methods.
Chapter four is the conclusion/summary part of this work. The overview of advantages and disadvantages of solar cell module are treated.
1.0 Introduction
Formation of solar cell using semi-conductor material is the act of using a semi-conductor to build a cell that can generate electricity when light (photons) falls on it. In the field of electrical and electronics engineering a semi-conductor simply means those materials whose conductivity lies somewhere between that of pure conductors and insulators. They are neither good conductors nor good insulators at normal room temperature (25oc). They are insulators at very low temperatures and good conductors at high temperature.
The Germanium (Ge) and silicon (Si) elements are the most important semi-conductor used in electronics.
A pure type of semi-conductor without doping is called an intrinsic semi-conductor, while extrinsic semiconductor is the one with doping. Where doping is the intentional addition of impurities to semi-conductors so as to increase its conductivity. For instance using silicon. When a silicon is doped with boron the resulting type is P-type, while if with phosphorous the resulting type is N-type. Hence solar cell has two parts the N-type and P-type side. And without this electric field, the cell would not work and this field forms when the N-type and P-type silicon are in contact.
Hence the electrons form the N-type side will rush to fill up the hole in the P-type side. Then when light in form of photons falls on the solar cell the energy frees electrons-hole pairs, with the presence of the electric field the electrons are caused to flow in a particular direction. Hence electric current is provided and the cells electric filed causes a voltage flow. Therefore the product of this voltage and the current gives the power.
Chapter Five
5.0 Conclusion And Recommendation
5.1 Conclusion
The solar cells that you see on calculators and satellites are photovoltaic cell modules (a group of cells electrically connected and packaged in one frame). Photovoltaic as the word implies (photo=light, voltaic=electricity), converts sun-light directly into electricity once used almost conclusive in space. Photovoltaic are used more and more in less exotic ways. They could even power your house using inverter to convert the voltage to alternating current source. The photovoltaic (PV) cells are made of special materials called semi-conductors such as silicon, which is currently the most commonly used.
Basically, when light strikes the cell, a certain portion of it is absorbed within the semi-conductor material. This means the energy of the absorbed light is transferred to the semi-conductor. The energy knocks electrons loose, allowing them to flow freely. Photovoltaic cells also have one or more electric fields that act to force electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current and by placing metal contacts on the top and bottom of the photovoltaic cells, we can draw that current off to use externally. This current together with cell’s voltage (which is as a result of its built-in electric fields) defines the power that the solar cell can produce.
5.2 Recommendation
This photovoltaic cell discussed above is comparable with those in the market and could be improved upon.
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