Tag: electrical and magnetic properties of solids

The highest temperature at which superconductivity has been observed is 23 K for alloys of niobium $(Nb _3Ge)$.

The n-type semiconductor can be produced  by doping impurity atoms of valence 5 i.e, pentavalent atoms like phosphorous and so electrons are majority charge carriers and Holes are minority charge carriers.

$Tl _2Ca _2Ba _2Cu _3O _{10}$ possess superconductivity at 125 K.

Superconductors have applications in electronics, building magnets, aviation, transportation (trains which move in air without rails) and power transmission.

The n-type semiconductors are obtained when $Si$ or $Ge$ are doped with elements of group 15, eg, Arsenic $(As)$, while p-type semiconductors are obtained when $Si$ or $Ge$ are doped with traces of group 13 , ie Indium $(In)$ , Boron $(B)$.

An extrinsic semiconductor is one that has been doped; during manufacture of the semiconductor crystal a trace element or chemical called a doping agent has been incorporated chemically into the crystal, for the purpose of giving it different electrical properties than the pure semiconductor crystal.

$p-$type semiconductors have a larger hole concentration than electron concentration. In p-type semiconductors, holes are the majority carriers and electrons are the minority carriers. $p-$type semiconductors are created by doping an intrinsic semiconductor with acceptor impurities. A common $p-$type dopant for silicon is boron or gallium. There will be no charge on the semiconductor.

$TiO _{ 3 }$ behaves as conductor or insulator depending on temperature because of variation of energy gap between valence band and conduction band with the variation of temperature.

An $n-$type semiconductor is made by adding a small amount of a Group-V element such as phosphorous ($P$) or arsenic ($As$) to the intrinsic semiconductor. Group-V elements have five valence electrons per atom.

The conductance through electrons is called n-type conduction and if through positive semiholes, it is called p-type conduction.
Doping involves preparation of semi-conductors by the presence of impurities in the intrinsic semiconductor.With donor impurities, we get n-type semi-conductors and with acceptor impurities, we get p-type semi-conductors.