The conductivity of semiconductor is between conductor and insulator, and its conductivity is affected by temperature, light and impurities. At room temperature, the conductivity of pure semiconductors (such as silicon and germanium) is relatively low, but when the temperature rises or is illuminated, electrons can obtain enough energy to transition from the valence band to the conduction band, resulting in an increase in conductivity. In addition, the conductivity of semiconductors can be significantly changed by doping impurities, which is called doping.
In the doping process, specific impurity atoms are introduced into the semiconductor lattice. These impurity atoms will replace the atoms in the lattice or enter the lattice gap, thus changing the electronic structure and conductivity of the material. According to the type of doped impurities, semiconductors can be divided into n type and p type.
N-type semiconductor
When the number of valence electrons of doped impurity atoms (such as phosphorus, arsenic, antimony) is more than that of semiconductor atoms, the extra electrons can move freely and become conductive free electrons. Such impurity atoms are called donor because they "feed" extra electrons. Because this type of doping increases the number of free electrons in the semiconductor, it is called n-type semiconductor, where "n" represents negative charge.
P-type semiconductor
On the other hand, when the number of valence electrons of doped impurity atoms (such as boron, gallium, aluminum) is less than that of semiconductor atoms, the impurity atoms will form holes in the lattice, because they need additional electrons to fill the defects on the valence band. Such impurity atoms are called acceptors. They "accept" electrons in the lattice to fill holes. Because this doping leads to an increase in the number of holes in the semiconductor, it is called a p-type semiconductor, where "p" represents positive charge.
Interaction between impurity and lattice
After the introduction of impurity atoms, impurity energy levels will be formed in the lattice. These energy levels are located in the forbidden band, close to the conduction band (for n-type) or the valence band (for p-type). The existence of impurity energy levels greatly reduces the energy required for electrons to transition from valence band to conduction band, so even at a lower temperature, there can be enough electrons or holes to participate in conduction. This is why doping can significantly improve the conductivity of semiconductors.
Importance of dot matrix
The lattice structure of semiconductor is the basis of crystal structure, which determines its physical and chemical properties. In semiconductor lattice, atoms are closely arranged through covalent bonds to form regular crystal structure. In the process of doping, impurity atoms must adapt to this lattice structure in order to effectively replace lattice atoms or insert lattice gaps. Lattice defects (such as vacancies and dislocations) will affect the electronic properties of semiconductors, including carrier mobility and lifetime, thus affecting the performance of devices.
Influence of temperature on semiconductor conductivity
The increase of temperature will increase the heat energy of electrons, so that more electrons can cross the gap into the conduction band, thus increasing the number of free electrons. Similarly, the number of holes will also increase, because the electrons in the valence band are excited to the conduction band, leaving holes. Therefore, an increase in temperature usually results in an increase in the conductivity of the semiconductor.
application
These properties of semiconductor materials make them indispensable in manufacturing various electronic devices. Doping technology can be used to manufacture diodes B1100LB-13-F Transistors, integrated circuits, etc. By precisely controlling the doping level and type, engineers can design devices with specific electrical characteristics, which are the basis of modern electronic equipment.
In a word, the conductivity of semiconductors is a complex phenomenon, involving the interaction of intrinsic properties of materials, doping, lattice defects, temperature and other factors. Through in-depth understanding and precise control of these factors, scientists and engineers can develop high-performance electronic and optoelectronic devices.
