How To Construct A Simple Photovoltaic / Solar Cell? High concentration of holes on one side of a junction and high concentration of electrons on the other side causes the two charge carriers to diffuse respectively to the other side of the junction. That junction formed is called PN junction. subjecting the surfaces in contact to a high temperature (not completely melting them so that they form one entity), a boundary or a junction is formed between them which is of the order 10 -3mm. When P and N type semiconductor are joined together by melting them I.e. They are formed when silicon or any other semiconductor is doped with a pentavalent element (element with a five valence electron in the outer shell). Holes (positive charge carriers) are the major charge carriers in this type of semiconductor.Įlectrons are the major charge carriers in this type of semiconductor. This kind of semiconductor is formed when a silicon, selenium or germanium is doped with a trivalent element (element with three valence electrons) like boron. When a semiconductor is doped, the following materials are found These types of semiconductors are not pure in that they are doped (substances which serve as impurities are being added in order to enhance its conductivity). Semiconductors of this type at zero degree Celsius have very little or no free holes and electrons for conduction. No impurity is added to improve their conductivity. These are semiconductors that are pure in their own form. We have two types of semiconductors which are intrinsic and extrinsic semiconductors. To understand this better, let’s see the different types of semiconductor material as the materials extensively used in the production of solar cells are semiconductors. Solar cells are made basically from semiconductors like silicon and selenium being the most widely used. By so doing EM radiation is converted to electrical energy. Do not get confused, the electrons or holes do not constitute to give the electrical charges. These holes serve as the positive charge carriers while the electrons serve as negative charge carriers. When EM radiation strikes the surface of the cell, it excites the electrons and as such cause them to jump from jump from one energy level (orbit) to the other leaving holes behind. As seen in the picture, the dark surface is the part that is exposed to sunlight. The principle operation of a solar cell is similar to conduction in a semiconductor like silicon. Basic Operating Principle Of A Photovoltaic / Solar Cell As stated above, the current generated is DC. Thus we can say that a solar cell is a semiconductor junction device that converts electromagnetic radiation reaching us from the sun to electrical energy. Solar cell converts em radiation to DC current. In solar cells, the amount of electrical energy generated by the cells depends on the intensity of em radiation that reaches the surface of the cell. In the course of this article, we will be making reference to sunlight as electromagnetic radiation (EM-radiation). Types of Solar Cells and Photovoltaic PanelsĪ solar cell is also known as photovoltaic cell which produces electric current when the surface is exposed to sunlight.
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