What are the types of semiconductor materials?

(1) element semiconductor. Elemental semiconductors refer to semiconductors composed of a single element, among which silicon and selenium were studied earlier. It is a solid material with semiconductor characteristics composed of the same elements, which is easily influenced by trace impurities and external conditions. At present, only silicon and germanium have good properties and are widely used, and selenium is used in electronic lighting and photoelectric fields. Silicon is widely used in semiconductor industry, mainly influenced by silicon dioxide. It can form a mask on device manufacturing, improve the stability of semiconductor devices, and is beneficial to automatic industrial production. [2]

(2) Inorganic composite semiconductor. Inorganic composite materials are mainly semiconductor materials composed of a single element, and of course there are also semiconductor materials composed of many elements. The main semiconductor characteristics are group I and V, VI and VII. The second group and the fourth, fifth, sixth and seventh groups; Third, fifth and sixth; The fourth group and the fourth group and the sixth group; Five and six; VI and VI compound compounds, but not all compounds can meet the requirements of semiconductor materials due to the characteristics of elements and manufacturing methods. This kind of semiconductor is mainly used in high-speed devices, and the transistor made of InP is faster than other materials, and is mainly used in optoelectronic integrated circuits and anti-nuclear radiation devices. For materials with high conductivity, they are mainly used in LED and other aspects. [2]

(3) Organic composite semiconductor. Organic compounds refer to compounds with carbon bonds in their molecules. The vertical superposition of organic compounds and carbon bonds can form a conduction band, which can enter the energy band through chemical addition, thus conducting electricity, thus forming an organic compound semiconductor. Compared with previous semiconductors, this semiconductor has the characteristics of low cost, good solubility and easy material processing. Conductivity can be controlled by controlling molecules, which has a wide range of applications, mainly for organic thin films, organic lighting and so on. [2]

(4) amorphous semiconductor. Also called amorphous semiconductor or glass semiconductor, it belongs to a kind of semiconductor material. Amorphous semiconductors, like other amorphous materials, are short-range ordered and long-range disordered 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 is whether there is a long program for atomic arrangement. It is difficult to control the performance of amorphous semiconductors. With the invention of technology, amorphous semiconductors began to be used. This manufacturing process is simple, and it is mainly used in engineering, and has a good effect in light absorption, mainly used in solar cells and liquid crystal displays. [2]

(5) Intrinsic semiconductor: A semiconductor without impurities and lattice defects is called an intrinsic semiconductor. At very low temperature, the valence band of semiconductor is full. After thermal excitation, some electrons in the valence band will cross the forbidden band and enter the empty band with higher energy. When there is an electron in the empty band, it becomes a conduction band. When an electron is missing from the valence band, a positively charged vacancy will be formed, which is called a hole. Hole conduction is not an actual movement, but an equivalence. When electrons conduct electricity, holes with equal charges will move in the opposite direction. [5] They generate directional motion under the action of external electric field, forming macroscopic current, which is called electron conduction and hole conduction respectively. This mixed conduction due to the generation of electron-hole pairs is called intrinsic conduction. Electrons in the conduction band will fall into holes, and electron-hole pairs will disappear. This is called recombination. The energy released during recombination becomes electromagnetic radiation (luminescence) or thermal vibration energy of crystal lattice (heating). At a certain temperature, the generation and recombination of electron-hole pairs coexist and reach a dynamic equilibrium. At this time, the semiconductor has a certain carrier density, so it has a certain resistivity. When the temperature rises, more electron-hole pairs will be produced, the carrier density will increase and the resistivity will decrease. Pure semiconductors without lattice defects have high resistivity and are not widely used in practice. [6]