1, semiconductor refers to the material whose conductivity is between conductor and insulator at room temperature. Semiconductors have applications in integrated circuits, consumer electronics, communication systems, photovoltaic power generation, lighting, high-power power conversion and other fields. For example, diodes are devices made of semiconductors. No matter from the perspective of science and technology or economic development, the importance of semiconductors is enormous. Most electronic products, such as computers, mobile phones or digital recorders, are closely related to semiconductors.

2. Conductor refers to a substance with low resistivity and easy to conduct current. A large number of freely movable charged particles in a conductor are called carriers. Under the action of external electric field, carriers move directionally, forming obvious current. Metal is the most common conductor. The valence electrons in the outermost layer of a metal atom can easily break away from the bondage of the nucleus and become free electrons, leaving positive ions (atomic solids) to form a regular lattice.

3. Insulators are also called dielectrics. Their resistivity is very high. Definition of insulator: An object that does not conduct electricity easily is called an insulator. There is no absolute boundary between insulator and conductor. Under certain conditions, an insulator can become a conductor. What should be noted here is: the reason for conducting electricity: whether it is a solid or a liquid, if electrons or ions can move freely in it, then it can conduct electricity. Without free-moving charge, under certain conditions, conductive particles can be produced, so it can also become a conductor.

4. Conductivity: The ability of an object to conduct current is called conductivity. The conductivity of various metals is different, usually silver has the best conductivity, followed by copper and gold. The conductivity of a solid refers to the long-distance migration of electrons or ions in the solid under the action of an electric field, which is usually dominated by a kind of charge carriers, such as: electron conductors, with electron carriers as the main body; Ionic conductivity based on ionic carriers; Mixed conductors have both carriers and ions.

Extended data:

From the point of view of energy band theory, the only difference between insulator and semiconductor is that the band gap of insulator is larger than that of semiconductor, so the carrier concentration in insulator is very small, which determines that the conductivity of insulator is very small. For some ionic crystals, there is another conduction mechanism-ionic conduction. It is caused by the movement of positive and negative ions under the action of external electric field. Generally speaking, the ionic conductivity is very small. The above-mentioned solid conductivity refers to crystalline solid, and the conductivity of amorphous solid has its own characteristics. See amorphous materials, amorphous semiconductors and amorphous dielectrics for details.