Semiconductors are materials that are not electrical conductors or insulators, but act like something in between, depending on conditions, such as temperature. The ability to vary the electrical properties of semiconductors has revolutionized the design and capabilities of modern electronics, making devices smaller and faster. The properties of semiconductors depend largely on what elements comprises them.
Glass vacuum tubes, the predecessors of semiconductors, were at one time used to direct electrical current through electronic devices, such as radios. Vacuum tubes were large, fragile and unwieldy, compared to semiconductors, according to FactsonFile.com. The electrical properties of semiconductors were first observed in the 1870s and are the basis of the integrated circuit, which is also known as a computer chip. Chips are much smaller than vacuum tubes and can perform many more functions while using much less power.
The most common element used in semiconductors is silicon, according to the Semiconductor Industry Association. In its pure state, silicon is almost an insulator. However, its electrical conductivity can be increased by doping, which refers to introducing minute amounts of other materials into the base material to create a different type of semiconductor. Combining different semiconductors allows the direction and flow of electrical signals to be carefully regulated, which is vital for computers, TVs, radios and other electronic devices to work properly.
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An intrinsic semiconductor is one in its pure state, like elemental silicon. Doping an intrinsic semiconductor creates an extrinsic semiconductor, with different properties. Compound or wide band gap semiconductors, which are made by combining two pure semiconductor materials, such as silicon and germanium, result in a wider range of properties that can be tailored to specific requirements, according to the Fulton School of Engineering.
Just as doping with minute amounts of boron or phosphorus is used to create intentional changes in a silicon semiconductor, contamination by unwanted impurities cause undesirable changes in electrical properties that may be severe. That is the reason semiconductors must be manufactured in conditions that are carefully controlled. The silicon used to make semiconductors is also grown specifically for that purpose, despite the fact that natural silicon is quite abundant.