Quasi-conductor are the detached type of matters. Such class was discovered in early 1980's but there were no needed technologies to carry on the further experiments. The research of semiconductors was carried on only in the 1920's. Russian physicists carried out a lot of researches. The results showed that semiconductors may help to generate the fluctuations and maintain them. But such parts as igct which are utilized nowadays were created significantly later. The most considerable event in the history of semiconductor devices was the creation of the first transistor by Bell company in 1949. Since then a lot of people all over the world become interested in such kind of matter as semiconductors.

Induced emission is actually a quite interesting characteristic of semiconductors that has been discovered for several tens of years. By usage of such principles as p - n barriers and heterojunction scientists managed to create laser device in the beginning of the 60's.

Today's producers can offer a broad spectrum of variant semiconductor devices to their customers, for instance power semiconductor devices. If there were no semiconductor devices used in the newest technologies, we won't have an opportunity to carry out such nice experiments which are important for other sciences.

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

Scientists haven't been interested in semiconductors for quite a long period of time. Abram Ioffe is a soviet scientist that started carrying out various experiments in field of semiconductors. This genius proposed some techniques of usage of semiconductors and every up to date system is based on these principles. There are electron conduction and hole conduction provided by semiconductor devices. It is related to the chemical mixture of the used admixtures. To get the characteristics which are needed for the research or appropriate use of device some admixtures are added to semiconductors.

Almost every sphere of newest technologies implies usage of semiconductors. Diodes, transistors and thyristors are the most often used systems. The wide application of semiconductors began not so long ago but today they are really broadly utilized. There are devices based on semiconductors which can turn luminous and heat energy into electric power and vice versa. With usage of electric power they can create heat and cold. Semiconductor systems may be found in radio receiver and quantum generator, in small atomic battery and in microprocessors. Workers can't do without semiconductor rectifiers, changers, power resistors and amplifiers. The use of semiconductors instead of tube devices allows to lower the sizes and masses of electronic devices. When semiconductors are utilized some significant characteristics as power and reliability are being improved much.

There are many various devices today, which considerably facilitate our life and all such inventions appear just thanks to the semiconductor devices.