Question

If a small amount of Arsenic impurity is added to a silicon semiconductor, then its electrical conductivity will:

• A. Decreases
• B. Increases
• C. Remains unchanged
• D. Becomes zero

Answer 1

The correct option is B Increases

The intentional introduction of impurities into an intrinsic semiconductor for the purpose of modulating its electrical, optical and structural properties is called dopping.
Doping can be carried out using electron rich impurities and electron deficient impurity.

Here, Arsenic (pentavalent) is an electron rich impurity since silicon is a semiconductor on which the dopping occurs. Thus, it is called n-type semiconductor. This will increase the electrical conductivity of semiconductor.