12.103P - Chemistry: Molecular Nature Of Matter And Change

Question

In the process of doping a semiconductor, certain impurities are added to increase its electrical conductivity. Explain this process for an n-type and a p-type semiconductor.

Step-by-Step Solution

Answer

When the conductivity of material lies between conductor and insulator then it is called a semiconductor.

Step 1: Definition

Doping is the process in which the conductivity of the semiconductor increases by adding an appropriate amount of suitable impurity.

Step 2: For an n-type semi-conductor

When group V elements (P or As) are doped in a semiconductor(group IV elements Si or Ge)then n-type semiconductors are obtained.

Hence, the conductivity increases by increasing the number of electrons available.

Step 3: For a p-type semi-conductor

P-type semiconductors are produced when group III elements (B or Ga) are doped in a semiconductor (group IV elements Si or Ge).

As a result, adding more holes causes the conductivity to rise.