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

Explanation

When a crystal of Si or Ge is formed, the trivalent atoms such as Al, B, In etc. are doped with small quantities in it, then the impurity atom is arranged in place of Si or Ge atom and the four Si or Ge atoms around it form a covalent bond with three atoms but fourth bond has an electron deficiency (absence or empty space), so that the hole is obtained, which is outlined in figure (a) and (b).

Since the holes has the property of attracting electrons, so the electron jump from nearest (neighbour) covalent bond in the crystal fills the hole so that the hole from which the electron is gone is now produced hole. Hence the p-type semiconductor gets a hole for conduction.
The trivalent foreign atom becomes effectively negatively charged when it shares fourth electron with neighbouring atom. Therefore, the dopant atom can be treated as core of a negative charge along with its associated hole as shown in figure (b).
Hence, one acceptor atom gives one hole. The total number of holes in the crystal is obtained in two ways. One from the number of impurity atoms which is much higher and second the release of electron from the bond of intrinsic semiconductors at room temperature creates hole whose number is very small.
Hence, in p-type semiconductor majority charge carriers is hole and minority charge carrier is electron.
The charge on hole is considered to be positive. From first letter of the word positive. This semiconductor is called p-type semiconductor.
`therefore` For p-type semiconductor `n_(e ) lt lt n_(h)`
where `n_(e )=` number of free electrons
`n_(h)=` number of hole
n-type or p-type semiconductor are electrically neutral. Because the charge of hole is the same as the charge (negative) at core of ionised atom and the opposite (positive) charge. Hence, charge on hole is positive. From first letter of the english word positive. This semiconductor is called p-type semiconductor.