There is a divided type of substances which is named quasi-conductors. In the first time this unique class was found in the 1890's but more thoroughly it began to be discovered only after the First World War in Europe and in Soviet Union. Russian physicists carried out lots of researches. The results demonstrated that semiconductors can help to generate the fluctuations and maintain them. During further years diodes were ejected by tubes. The most significant event in the history of semiconductor devices was the invention of the first transistor by Bell company in 1949. That was the beginning of the epoch of semiconductor technologies.
A lot of scientists carry out a great deal of experiments simply to get more knowledge about such feature of semiconductors as stimulated emission. By usage of such principles as p - n barriers and heterojunction scientists managed to create laser device in the beginning of the 60's.
Modern developers can offer a wide spectrum of variant semiconductor devices to their consumers, for instance diodes. In case there were no semiconductor devices utilized in the newest technologies, we won't have an opportunity to carry out such nice researches that are significant for other sciences.
The basic reason why semiconductors are believed to be the detached class is that they have a conductivity that is between the conductivities of metals and isolators. Such substances as germanium, silicon, selenium and several others are believed to be semiconductors.
It sounds a bit strange but physicists didn't want to carry out experiments of semiconductors for a long time. Abram Ioffe is a Russian physicist that began performing different researches in area of semiconductors. He discovered that semiconductors are the divided class of crystals with some definite characteristics. Any semiconductor device has got such main characteristics as electron and hole conduction. Such features may be modified by usage of adding some admixtures or changing temperature. To get the features which are required for the research or proper usage of device some admixtures are added to semiconductors.
The most important semiconductor systems which are utilized in technologies are diodes, transistors and thyristors that are founded on elements with electron and hole conductions. Their unique features are frequently utilized nowadays, but they became spread just ten years ago. There are systems based on semiconductors which may turn luminous and heat energy into electricity and vice versa. Heat and cold may be produced by some types of semiconductors. Semiconductor systems may be found in radio receiver and quantum generator, in small atomic battery and in microprocessors. Such devices as power resistors are commonly used in any construction related to the electricity. The weight and overall dimensions of semiconductor systems are significantly smaller than their tube analogues. The analogue systems are not equal in case we talk about their reliability and power. Tube falls behind.
There are a lot of different systems nowadays, which considerably facilitate our life and all such inventions appear just thanks to the semiconductor systems.