Introduction to Semiconductors

Semiconductor devices are the basic components that make up electronic circuits, and the materials used are semiconductor materials. Semiconductor materials refer to substances with conductivity between conductors and insulators. In addition to having conductivity between conductors and semiconductors, semiconductors also have the following properties: increasing temperature can significantly improve the conductivity of semiconductors. For example, when the temperature of pure SiSiSi increases from 30? C30 ^ circle C30 ^ circle C to 20? When C20 ^ circ C20 ^ circ C is used, a double increase in resistivity can significantly alter the conductivity of semiconductors by increasing the content of trace impurities (with or without, how much).

For example, if one impurity atom (+3 valence element and+5 valence element) is added to every 1 million SiSiSi atoms, then at room temperature (27? C27 ^ circle C27 ^ circle C, why is it 27? C27 ^ circle C27 ^ circle C at room temperature? Because the absolute temperature is an integer, T=273+tT=273+tT=273+t, the closest TTT is 300k300k, so t is 27? C27 ^ circle C27 ^ circle C), its resistivity is 214000 Ω? Cm214000 Omega cdot cm214000 Omega cdot cm decreases to 0.2 Ω? Cm0.2 Omega cdot cm0.2 Omega cdot cm, light can significantly improve the conductivity of semiconductors. For example, CdSCdSCdS thin films deposited on insulating substrates have a resistance value of about tens of M Ω M OmegaM Omega in the absence of light, while the resistance value is about tens of K Ω K OmegaK Omega under light. Additionally, magnetic and electric fields can also significantly change the conductivity of semiconductors, so semiconductors have a conductivity between conductors and insulators, In addition, it is also a material that is prone to significant changes in its own properties due to changes in external light, heat, magnetism, electricity, and trace impurity content.

If semiconductors have such good properties, we can make use of them, especially the diodes, transistors, and field-effect transistors introduced later, which use the content of trace impurities to significantly change the conductivity of semiconductors.