The difference between semiconductors and superconductors is that semiconductors are materials that have properties that lie between conductors and insulators, while superconductors are those materials that act strangely when cooled down.
What are Semiconductors?
Semiconductors are those materials that are neither good conductors nor good insulators. Their conductivity is intermediate between conductors and insulators. Silicon and germanium are semiconductor elements, at room temperature.
The conducting of semiconductors is charged by temperature-applied voltage or incident light. Pure silicon or germanium are poor conductors but by doping with impurities charges the conductivity by a lot. The temperature coefficient of resistivity is negative for semiconductors.
The energy states of electrons in any material are quantized and grouped together in bands. Between the band, there is an energy gap that contains no states that an electron can occupy. This is called the forbidden energy gap. An electron can jump from the valence band the outermost band to the conduction band.
In a conductor, the valence band and conduction bands are overlapped. A small applied electric field causes electrons to contribute electric current in conductors. In insulators, this forbidden energy gap is more than 3ev and no electron can jump from the valence band to the conduction band. So no free electron is available in the insulator to contribute the electric current in insulators.
In the semiconductor shows, the energy gap is very narrow less than 2ev. In silicon, it is only 0.7 ev. So at the ordinary temperature, some electrons can jump from the valence band to the conduction band and contribute currently.
The resistivity of conductors increases with increases in temperature so they have the temperature coefficient resistivity. White in temperature, more electrons acquire energy to jump from the valence band to the conduction band so increasing the conductivity and decreasing the resistivity of semiconductor material by the increase in temperature.
What is a Super Conductor?
If the resistivity of a material is zero it is called a superconductor, and if a current is established in a superconductor material, it should persist forever, even with no electric field present.
In an ordinary conductor the resistivity increase with an increase in temperature, so by decreasing temperature the resistivity should decrease. But there is a finite value of resistivity at the lowest temperature. The superconductivity was first discovered in mercury at 4k. It is not a gradual decrease in resistivity but at 4k the material resistivity becomes suddenly zero and becomes a superconductor. Now some ceramic materials are discovered which are the superconductor at a relatively high temperature of almost 90k.
Microscopic pairs of superconductivity
The best room-temperature conductors like gold, and copper do not show any superconductivity at all.
These materials have a single weakly bound electron that contributes to conductivity. Superconductors depend on the motion of highly correlated pairs of electrons.
Generally, electrons do not form pairs, a special circumstance is required two electrons each interact strongly with a lattice and with each other while in order any conductor, the electrons interact with the lattice weakly.
Applications of superconductors in physics
These are the following applications of superconductor material is suggested.
- Energy can be transported and stored in wires without resistance loads.
- Superconductors electromagnetic can produce large magnetic fields than conventional electromagnets. They can use in large accelerators and levitated trains.
- As superconductor components in electronic circuits do not produce Joule heating. So smaller circuits can be produced by the use of superconductors.