Led floodlight 30w little knowledge: conductivity can not distinguish between semiconductor and metal, insulator

The physical quantity that characterizes the ease with which a substance conducts is called conductivity, and the unit is Sem (Siemens centimeter). The resistivity is a physical quantity (unit: 2 cm) which indicates how difficult the substance is to conduct, and is the reciprocal of the conductivity. Field 1 shows the relationship between the conductivity of various substances and the band gap. It can be seen that the larger the band, the lower the conductivity.

The electrical conductivity of the metal was observed. The conductivity of copper (Cu) was 6 × 10 ° S/cm, the conductivity of aluminum (Al) was 4 × 10 Scm, and the conductivity of mercury (Hg) was 1 × 10 S/cm. Although the non-conducting body is a substance that cannot conduct current, it is not completely non-conductive, and its electrical conductivity is less than 104 S/cm. On the other hand, the semiconductor conductivity is between 10 S/cm of the conductor and 10-8 Scm of the insulator. Diamonds previously considered to be insulators and recently discovered impurity additives are likely to have a conductivity of 102 Scm. Now that the body tubes and LEDs have been successfully produced, they have also become members of the semiconductor. Therefore, the magnitude of conductivity cannot be used as a standard for distinguishing conductors, semiconductors, and insulators.