Which one of the following statement isFALSE ? [2010]a)Pure Si doped with trivalent impurities givesa p-type semiconductorb)Majority carriers in a n-type semiconductorare holesc)Minority carriers in a p-type semiconductorare electronsd)The resistance of intrinsic semiconductordecreases with increase of temperatureCorrect answer is option 'B'. Can you explain this answer?

Question

Which one of the following statement isFALSE ?  [2010]a)Pure Si doped with trivalent impurities givesa p-type semiconductorb)Majority carriers in a n-type semiconductorare holesc)Minority carriers in a p-type semiconductorare electronsd)The resistance of intrinsic semiconductordecreases with increase of temperatureCorrect answer is option 'B'. Can you explain this answer?

Answer

False Statement:
The majority carriers in an n-type semiconductor are holes.

Explanation:
Semiconductors are materials that have a conductivity between that of conductors and insulators. They have a valence band, which is fully occupied by electrons, and a conduction band, which is empty. For a material to conduct electricity, there must be some electrons that can move from the valence band to the conduction band.

Doping is the process of intentionally adding impurities to a semiconductor to change its electrical properties. When a trivalent impurity, such as boron, is added to pure silicon, it creates a p-type semiconductor. This is because the trivalent impurity has one less valence electron than silicon, creating a 'hole' in the valence band which behaves like a positively charged carrier.

On the other hand, when a pentavalent impurity, such as phosphorus, is added to pure silicon, it creates an n-type semiconductor. This is because the pentavalent impurity has one more valence electron than silicon, creating an excess of negatively charged carriers in the conduction band.

Therefore, the false statement is that the majority carriers in an n-type semiconductor are holes. In fact, the majority carriers in an n-type semiconductor are electrons, while the minority carriers are holes. The opposite is true for a p-type semiconductor, where the majority carriers are holes and the minority carriers are electrons.

Additionally, it is true that the resistance of intrinsic semiconductors decreases with an increase in temperature. This is because at higher temperatures, more electrons are excited from the valence band to the conduction band, increasing the conductivity of the material.

Answer

P-type semiconductor are obtained by adding a small amount of trivalent impurity to a pure sample of semiconductor(Ge).

Majority charge carriers-holes

Minority charge carries-electrons

•n-type semiconductor are obtained by adding a small amount of pentavalent impurity to a pure sample of semiconductor (Ge).

Majority charge carries-electrons

Hence from the above statement b is false

Answer

Option b
majority carriers in a n-type semiconductor is electron with pentavalent impurities .
but in case of p- type majority carriers is holes with trivalent impurities.

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