Quasi-conductors are considered to be a special kind of chemical elements. In the first time that unique class was discovered in the 1890’s but more completely it started to be discovered just after the First World War in Europe and in Soviet Union. Russian physicists carried out lots of experiments. The results showed that semiconductors can help to generate the fluctuations and maintain them. There was no opportunity to create some sophisticated devices as igct. The most considerable event in the history of semiconductor devices was the invention of the first transistor by Bell corporation in 1949. That was the beginning of the era of semiconductor technologies.

A lot of scientists carry out a great deal of experiments simply to gain more knowledge about such characteristic of semiconductors as stimulated radiation. First laser device was created with utilizing of semiconductors. The first version was based on p - n barriers, the latest ones - on heterojunction.

Today’s producers can propose a broad spectrum of different semiconductor devices to their consumers, for example pulsed power devices. If there were no semiconductor systems used in the newest technologies, we won’t have an opportunity to carry out such nice experiments which are significant for other sciences.

The conductivity of semiconductors lies in diapason between conductivity of metals and conductivity of isolators. This characteristic is caused the division of semiconductors as a divided class. There are some elements that are basically utilized to create the semiconductor devices. They are germanium, selenium, silicon, etc.

For quite long period of time semiconductors haven’t drawn the attention of physicists and engineers. The first experiments of semiconductors were begun by famous soviet scientist Abram Ioffe. This genius offered some methods of usage of semiconductors and every modern device is based on such principles. Any semiconductor device has such main features as electron and hole conduction. Such characteristics can be changed by usage of adding some admixtures or modifying temperature. The admixtures affect significantly on the electron conduction of the semiconductors.

Almost every area of newest technologies implies use of semiconductors. Diodes, transistors and thyristors are the most often used systems. Semiconductors are widely used as their characteristics are useful for almost every electric device. They are used to transform light and heat energy into electric energy and vice versa. Heat and cold may be developed by some types of semiconductors. Such devices as radio receivers, atomic batteries, quantum generator, microprocessors etc include semiconductors. Such devices as fuses are commonly utilized in any construction related to the electricity. The mass and overall dimensions of semiconductor devices are considerably smaller than their tube variants. The analogue systems are not equal if we speak about their reliability and power. Tube drops behind.

We can’t imagine how the humankind can exist without lots of devices which are based on usage of semiconductors.