Question

Addition of trivalent impurity to a semiconductor creates many

A.)Holes
B.)Free electrons
C.)Valence electrons
D.)Bound electrons

Answer 1

Hint: The trivalent impurity are the doping materials having three electrons in the outermost shell of the atom. The pure semiconductor is converted into p and n types of the semiconductor. These semiconductors are more conductive than pure semiconductors.

Complete answer:
The semiconductors are the material having four electrons in the outermost shell. These elements can neither lose nor gain four electrons. So, these elements share the electrons with other atoms of the same elements. As these elements are combined with the element of the same element, these are known as the intrinsic semiconductors. The conductivity of the intrinsic semiconductors is very low. The temperature of the intrinsic semiconductor is increased to very high value. So, at high temperature the intrinsic semiconductors are conductive.

The intrinsic semiconductor is doped with the trivalent impurities added. So, three electrons combined to three neighbour atoms. One electron pair creates the space for electrons in the intrinsic semiconductors. This space for electrons is commonly known as the holes.
The semiconductor is known as the p-type semiconductors and has an excess of holes.

So (A) option is correct here.

Additional Information:
The elements are classified in three types of the materials:

(i)Metals: These materials are good conductors of heat and electricity.
(ii)Non-metals: These materials are bad conductor of heat and electricity
(iii)Semiconductors: The conductivity of the semiconductors lie in between the conductivity of the metals and non-metals.


Note:The intrinsic semiconductor is doped with pentavalent impurities. The electrons are produced in the semiconductor. This semiconductor is known as the n type of the semiconductor.