Quasi-conductor are the divided class of substances. Such type was researched in early 1980's but there were no needed technologies to perform the further experiments. The analysis of semiconductors was carried on just in the 1920's. The first successful experiment was performed by the Russian physicists in 1923. They proved that semiconductors may be utilized to generate fluctuations. During further years igbt modules were excluded by tubes. 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 start of the epoch of semiconductor technologies.

The concern to optical features of semiconductors revived due to discovery of simulated emission in semiconductors. By means of such principles as p - n barriers and heterojunction physicists managed to design laser device in the beginning of the 60's.

Today we may see a great deal of various pulsed power devices which work with assistance of use of semiconductors. Today it is not possible to perform any researches without some modern technologies which are based on use of semiconductors.

The main reason why semiconductors are believed to be the divided class is that they have got a conductivity which is between the conductivities of metals and isolators. There are some elements that are mainly utilized to develop the semiconductor devices. They are germanium, selenium, silicon, etc.

Physicists haven't been interested in semiconductors for quite a long period of time. The first experiments of semiconductors were started by famous Russian physicist Abram Ioffe. He found that semiconductors are the divided type of crystals with some unique features. There are electron conduction and hole conduction provided by semiconductor devices. These characteristics can be modified by usage of adding some admixtures or changing temperature. To get the features which are needed for the experiment or proper use of device some admixtures are added to semiconductors.

Almost every area of newest technologies means usage of semiconductors. Diodes, transistors and thyristors are the most often used devices. The wide application of semiconductors started not so long ago but today they are truly widely used. There is an ability to transform almost every type of energy into electric power by mans of semiconductors. With usage of electric power they may develop heat and cold. Semiconductor devices may be found in radio receiver and quantum generator, in small atomic battery and in microprocessors. Workers can't do without semiconductor rectifiers, changers, fuses and amplifiers. The use of semiconductors instead of tube devices allows to lower the overall dimensions and masses of electronic devices. The analogue systems are not equal if we speak about their reliability and power. Tube falls behind.

We can't imagine how the humankind can do without lots of devices that are based on utilizing of semiconductors.