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Semiconductors are considered to be a unique kind of chemical elements. At first that unique class was found in the 1890's but more completely it started to be discovered just after the First World War in Europe and in Soviet Union. The first successful research was performed by the Russian physicists in 1923. They proved that semiconductors can be used to generate fluctuations. But such devices as semiconductor assembly that are used today were created considerably later. The most significant event in the history of semiconductor devices was the creation of the first transistor by Bell corporation in 1949. Since then a lot of persons all over the world become interested in such type of matter as semiconductors.

The interest to optical features of semiconductors revived because of research of induced emission in semiconductors. First laser system was developed with usage of semiconductors. The first variant was based on p - n barriers, the latest ones - on heterojunction.

Today's developers may propose a broad spectrum of variant semiconductor devices to their consumers, for example asymmetric GTO thyristors. In case there were no semiconductor devices utilized in the newest technologies, we won't have an opportunity to carry out such nice experiments that are important for other sciences.

The conductivity of semiconductors lies in range between conductivity of metals and conductivity of isolators. This feature is produced the division of semiconductors as a detached class. There are some substances which are mainly used to create 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 man who decided to gain more information about semiconductors was Abram Ioffe - Russian physicist. He found that semiconductors are the special type of crystals with some definite features. There are electron conduction and hole conduction developed by semiconductor systems. The characteristics of semiconductor are dependant on the conditions they are situated. For instance, by utilizing of some admixtures the value of electron conduction may be modified.

The most significant semiconductor devices which are utilized in technologies are diodes, transistors and thyristors which are based on elements with electron and hole conductions. Their sophisticated characteristics are widely used nowadays, but they became spread just ten years ago. There is a possibility to convert almost every kind of energy into electric power by usage of semiconductors. Some of them are even able to develop cold and heat. Semiconductors execute the basic functions in many different devices: atomic batteries, quantum generators, processors and even simple radio receivers. Almost every worker that works in company related to electricity ought to know how important the power resistors are. If we match devices equipped with semiconductors and tube devices we will realize that semiconductors are considerably smaller and lighter. When semiconductors are utilized some significant characteristics as power and reliability are being developed a lot.

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