Classification And Performance Of Semiconductors

(1) Element semiconductors. Element semiconductors refer to semiconductors composed of a single element, among which silicon and selenium have been studied relatively early. It is a solid material with semiconductor properties composed of the same elements and is easily affected by trace impurities and external conditions. At present, only silicon and germanium have good performance and are widely used. Selenium is used in the fields of electronic lighting and optoelectronics. Silicon is widely used in the semiconductor industry, which is mainly affected by silicon dioxide. It can form a mask in device production, improve the stability of semiconductor devices, and facilitate automated industrial production.
(2) Inorganic composite semiconductors. Inorganic composites mainly consist of semiconductor materials composed of a single element. Of course, there are also semiconductor materials composed of multiple elements. The main semiconductor properties are Group I and Groups V, VI, and VII; Group II and Groups IV, V, VI, and VII; III Combination compounds of Group V and Group VI; Group IV and Group IV and VI; Group V and Group VI; Group VI and Group VI. However, affected by the characteristics of the elements and the way they are made, not all compounds can be qualified as semiconductor materials. requirements. This semiconductor is mainly used in high-speed devices. The speed of transistors made of InP is higher than that of other materials. It is mainly used in optoelectronic integrated circuits and nuclear radiation-resistant devices. For materials with high conductivity, they are mainly used in LEDs and other aspects.
(3) Organic composite semiconductors. Organic compounds refer to compounds containing carbon bonds in their molecules. By superimposing the organic compounds and carbon bonds vertically, they can form a conduction band. Through the addition of chemicals, they can enter the energy band, so that conductivity can occur, thus forming Organic compound semiconductors. Compared with previous semiconductors, this semiconductor has the characteristics of low cost, good solubility, and easy material processing. The conductive properties can be controlled by controlling molecules. It has a wide range of applications and is mainly used in organic films, organic lighting, etc.
(4) Amorphous semiconductor. It is also called an amorphous semiconductor or a glass semiconductor and is a type of semiconducting material. Amorphous semiconductors, like other amorphous materials, have short-range order and long-range disorder structures. It mainly forms amorphous silicon by changing the relative position of atoms and changing the original periodic arrangement. The main difference between crystalline and amorphous states is whether the atomic arrangement has long order. It is difficult to control the properties of amorphous semiconductors. With the invention of technology, amorphous semiconductors began to be used. This production process is simple and is mainly used in engineering. It has a good effect in light absorption and is mainly used in solar cells and liquid crystal displays.
(5) Intrinsic semiconductors: Semiconductors that do not contain impurities and have no lattice defects are called intrinsic semiconductors. At extremely low temperatures, the valence band of a semiconductor is a full band. After thermal excitation, some electrons in the valence band will cross the forbidden band and enter an empty band with higher energy. The empty band will become the conduction band after electrons are present in the valence band. The absence of an electron creates a positively charged vacancy, called a hole. Hole conduction is not an actual movement, but an equivalent. When electrons conduct electricity, holes of equal charge will move in the opposite direction. They produce directional motion under the action of an external electric field to form macroscopic currents, which are called electron conduction and hole conduction respectively. This mixed conductivity due to the generation of electron-hole pairs is called intrinsic conductivity. Electrons in the conduction band fall into holes and the electron-hole pairs disappear, which is called recombination. The energy released during recombination becomes electromagnetic radiation (luminescence) or thermal vibration energy of the crystal lattice (heating). At a certain temperature, the generation and recombination of electron-hole pairs exist simultaneously and reach dynamic equilibrium. At this time, the semiconductor has a certain carrier density and thus a certain resistivity. As the temperature increases, more electron-hole pairs are produced, the carrier density increases, and the resistivity decreases. Pure semiconductors without lattice defects have large resistivities and have few practical applications.