There is a detached type of matters which is named semiconductors. In the first time this unique class was found in the 1890's but more completely it began to be researched only after the First World War in Europe and in Soviet Union. In 1923 Russian physicists proved the ability of usage of semiconductor-metal contacts to accelerate the generation of fluctuations. But such devices as semiconductor assembly which are used today were invented significantly later. Just in the beginning of the 60's with the invention of transistors in 1949 the wide usage of crystal detectors started. The intensive studying of the characteristics of semiconductors was started at the same time.

The concern to optical characteristics of semiconductors revived due to discovery of induced emission in semiconductors. By means of such principles as p - n barriers and heterojunction scientists managed to create laser device in the beginning of the 60's.

Nowadays we can see a great deal of different pulsed power devices which operate with help of usage of semiconductors. Today it is not possible to perform any experiments without some modern technologies which are founded on use of semiconductors.

Semiconductors are a broad class of substances that are characterized by the value of conductivity that is situated between the conductivities of metals and isolators. Such substances as germanium, silicon, selenium and several others are considered to be semiconductors.

It sounds a little strange but scientists didn't want to perform experiments of semiconductors for a long time. Abram Ioffe is a Russian physicist who started carrying out different researches in field of semiconductors. He discovered that semiconductors are the divided type of crystals with some unique characteristics. Every semiconductor device has got such basic characteristics as electron and hole conduction. It is dependant on the chemical composition of the introduced admixtures. For instance, by usage of some admixtures the value of electron conduction may be modified.

Almost every sphere of newest technologies means use of semiconductors. Diodes, transistors and thyristors are the most often utilized systems. The broad application of semiconductors started not so long ago but nowadays they are truly broadly utilized. There is a possibility to transform almost every type of energy into electric power by mans of semiconductors. Heat and cold can be developed by some kinds of semiconductors. Semiconductors execute the basic functions in lots of various devices: atomic batteries, quantum generators, processors and even primitive radio receivers. Such devices as voltage sensors are commonly utilized in any construction connected to the electricity. The mass and overall dimensions of semiconductor systems are significantly smaller than their tube analogues. The analogue systems are not equal if we talk about their reliability and power. Tube drops behind.

There are a lot of different devices today, which considerably facilitate our life and all such inventions appear only owing to the semiconductor devices.