What is n-type semiconductor? Name the majority and minority carriers in it.

Explanation

Suppose we dope Si or Ge with a pentravalent element, such as arsenic, aluminium or indium occupies the position of an atom in the crystal lattice of Si, four of its electrons bond with the four silicon neighbours while the fifth remains very weakly bound to its parent atom. This is because the four electrons participating in bonding are seen at part of the effective core of the atom by the fifth electron.

As a result the ionisation energy required to set this electron free is very small and even at room temperature it will be free to move in the lattice of the semiconductor.
The energy required is `~0.01` eV for germanium and 0.05 eV for silicon to separate this electron from its atom. This energy required to jump the forbidden band is about 0.72 eV for Ge and about 1.1 eV for Si at room temperature in the intrinsic semiconductor and for Si it is almost much less than 1.1 eV.
Thus, the pentavalent dopant is donating one extra electron for conduction and hence is known as donor impurity.
The number of electrons made available for conduction by dopant atoms depends stronglevel upon the doping level and is independent any increase in ambient temperature.
In addition, the number of free electrons and holes, increases weakly with temperature. When number of free electron `n_(e )` increases due to impurity and electrons increase with decreasing number of hole (with electron) connection, as a result mejority carriers electron `(n_(e ))` is greater and the number of minority carrier holes `(n_(h))` is lessen
`therefore ` In n-type semiconductor `n_(e ) gt gt n_(h)`
The majority charge carrier in n-type semiconductor is electrons and charge or electron is negative and the negative is called N in english so from the first letter it is called n-type semiconductor.