Question

We can not make \(\mathrm{p}-\mathrm{n}\) junction diode by making \(\mathrm{P}\) type semi-conductor join with N-type semi-conductor, because (A) Inter-atomic spacing becomes less than \(1 \mathrm{~A}^{\circ}\) (B) P-type will repel N-type (C) There will be discontinuity for the flowing charge carriers (D) semi-conducting properties will be lost

Short answer

Analysis of each option reveals none of them prevent the formation of a p-n junction diode by joining a P-type and an N-type semiconductor. Option A is invalid since the inter-atomic spacing depends on the crystal lattice of the semiconductor, not on the junction. Option B is incorrect as both P-type and N-type semiconductors are made from the same base material and do not repel each other. Option C does not hold as the continuous flow of charge carriers is enabled by the applied voltage across the junction, despite recombination at the junction. Option D is untrue as the semiconducting properties of each semiconductor are preserved when joined. Thus, we can construct a p-n junction by connecting a P-type and an N-type semiconductor.

Step-by-step solution

Understanding P-type and N-type Semiconductors

A P-type semiconductor has an abundance of positive charge carriers (holes) while an N-type semiconductor has an abundance of negative charge carriers (electrons). When a P-type semiconductor is joined with an N-type semiconductor, a p-n junction is formed, which is the basis of many semiconductor devices like diodes, transistors, etc. Hence, the statement "We cannot make p-n junction diode by making P-type semiconductor join with N-type semiconductor" is incorrect. However, we will examine the given options and explain why they are not valid reasons to prevent the formation of a p-n junction diode.

Option A: Inter-atomic spacing becomes less than 1 Å

Inter-atomic spacing is a property of the crystal lattice of the semiconductor material and is not affected by joining P-type and N-type semiconductors. So, this option is not a valid reason to prevent the formation of a p-n junction diode.

Option B: P-type will repel N-type

Both P-type and N-type semiconductors are made of the same base material (silicon or germanium), and there is no reason for them to repel each other when they are joined. So, this option is not a valid reason to prevent the formation of a p-n junction diode.

Option C: There will be discontinuity for the flowing charge carriers

When a P-type semiconductor is joined with an N-type semiconductor, a p-n junction is formed. At this junction, electrons and holes recombine, resulting in a depletion region with no free charge carriers. However, the flow of charge carriers can still happen through the applied voltage across the junction. So, this option is not a valid reason to prevent the formation of a p-n junction diode.

Option D: Semi-conducting properties will be lost

When a P-type semiconductor is joined with an N-type semiconductor, their individual properties do not change. The P-N junction diode formed by joining them can still make use of their semi-conducting properties for its working as a rectifier or an electronic switch. So, this option is not a valid reason to prevent the formation of a p-n junction diode. To summarize, all the given options (A, B, C, and D) are not valid reasons to prevent the formation of a p-n junction diode when a P-type semiconductor is joined with an N-type semiconductor.