Question

Intrinsic semiconductor is electrically neutral, extrinsic semiconductor having large number of current carriers would be:

• A. electricallyneutral
• B. positively charged or negatively charged depending upon the type of impurity that has been added
• C. positively charged
• D. negatively charged

Answer 1

Answer: (A)

electricallyneutral

Answer 2

In an extrinsic semiconductor, substitutional impurity atoms donate (or accept) electrons. Although these impurities become ionized (donor atoms become positive and acceptor atoms become negative), the overall semiconductor remains electrically neutral.

1. Doping Process:

   • In n-type, donor atoms donate electrons, becoming positively charged.
   • In p-type, acceptor atoms accept electrons, becoming negatively charged.

2. Charge Balanced:

   • The free electrons (or holes) balance the charge of the ionized dopants.
   • As a result, the net charge over the whole semiconductor remains zero.