Question

Which kinds of defects are introduced by doping?
a.) Dislocation Defects
b.) Schottky defects
c.) Frenkel defects
d.) Electronics defects

Answer 1

Hint: To answer the correct option, we should first know about doping. We should also know about defects and their types.


Complete step by step solution:
First of all we should know about doping. We should know that doping is the process of adding impurities to intrinsic semiconductors to alter their properties. For example, we can increase the conductivity by doping.
We will now define the defects. We can say that defects can be defined in which there will be irregularities in the arrangements of constituent particles. On the basis of irregular arrangement, the defect may be a point or line defect.
Let us now discuss each option to check which option is correct.

Dislocation defects: We should know that dislocation is a type of defect, in which an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to slide over each other at low stress levels and is known as glide or slip. So, in this defect there is no addition or can say there is no doping. From this we can say that this option is incorrect.
Schottky defects: We should know that this defect occurs due to the missing of the number of cations and anions from the lattice site. From this we can say that this option is also incorrect.

Frenkel defects: We should know that in this type of defect, some cations are missing from their lattice site and occupy the interstitial site of the lattice. This defect is also not introduced by doping.

Electronics defect: We should know that the electron deficient bond formed by the release of an electron which we called a hole. If we apply the electric field the positive holes move in a direction opposite to that of the electrons and conduct electricity. The electrons and holes in solids give rise to electronic defects. This type of defect is introduced by doping.

From the above discussion, we can say that option D is the correct answer.


Note: We should now take the case of ZnO. We should note that in ZnO, there is an excess positive ion located in the interstitial site. When ZnO is heated it loses oxygen reversibly. The excess \[\text{Z}{{\text{n}}^{2+}}\]ions are occupied in the interstitial sites for maintaining the neutrality, electrons are enclosed in the neighbouring interstitial sites. On heating, ZnO turns yellow by losing oxygen. This is called metal excess defect.