Semiconductors are the divided type of substances. People got known about these substances in the end of the 19th century, but only in the 20th century scientists managed to get more knowledge about them. Russian physicists carried out lots of experiments. The results showed that semiconductors can help to accelerate the fluctuations and maintain them. During further years diodes were ejected by tubes. First transistor was created in Bell's laboratory in 1949. This event influenced the quick development of semiconductor devices. Since then a lot of persons all over the world become interested in such type of matter as semiconductors.

Induced emission is actually a quite interesting feature of semiconductors that has been researched for several tens of years. By usage of such principles as p - n barriers and heterojunction physicists managed to design laser system in the beginning of the 60's.

Nowadays we can see a huge amount of different asymmetric GTO thyristors which work with help of use of semiconductors. Nowadays it is impossible to carry out any experiments without some new technologies that are based on use of semiconductors.

The main reason why semiconductors are considered to be the detached kind is that they have got a conductivity that is between the conductivities of metals and isolators. There are some substances which are mainly utilized to create the semiconductor devices. They are germanium, selenium, silicon, etc.

For quite long period of time semiconductors haven't got the attention of scientists and engineers. The first man who decided to get more information about semiconductors was Abram Ioffe - Russian scientist. He noticed that this wonderful sort of substance has some unique characteristics and determined how they may be used. Every semiconductor device has got such basic characteristics as electron and hole conduction. The features of semiconductor are dependant on the conditions they are placed. For example, by usage of some admixtures the value of electron conduction can be changed.

Almost every sphere of newest technologies implies usage of semiconductors. Diodes, transistors and thyristors are the most often used devices. The wide application of semiconductors began not so long ago but nowadays they are truly broadly used. There are systems based on semiconductors that may convert luminous and heat energy into electric power and vice versa. Several of them are even able to develop cold and heat. Semiconductor devices may be found in radio receiver and quantum generator, in little atomic battery and in microprocessors. Such systems as current sensors are commonly used in any construction connected to the electricity. In case we match devices operating on semiconductors and tube devices we will realize that semiconductors are significantly smaller and lighter. The analogue devices are not equal if we talk about their reliability and power. Tube falls behind.

There are a lot of different devices nowadays, which significantly ease our life and all these inventions appear just thanks to the semiconductor devices.