Addition of pentavalent impurity to a semiconductor creates many ……..Select one:a. Free electronsb. Bound electronsc. Holesd. Valence electrons

The addition of a pentavalent impurity to a semiconductor creates many free electrons. So, the correct answer is a. Free electrons.

Here's why:

Semiconductors are materials that have properties between conductors and insulators. In their pure form, semiconductors do not conduct electricity very well. However, their conductivity can be increased by adding impurities, a process known as doping.

When a pentavalent impurity (an element with five valence electrons such as phosphorus, arsenic, or antimony) is added to a semiconductor (like silicon or germanium which has four valence electrons), four of the impurity's electrons form covalent bonds with the four adjacent semiconductor atoms. The fifth electron is loosely bound to the impurity atom and can easily move to the conduction band, becoming a free electron.

These free electrons increase the conductivity of the semiconductor, making it an n-type (negative-type) semiconductor because of the negative charge of the free electrons.