In an \(\mathrm{n\text-}\)type semiconductor, which of the following statement is true?
1. Electrons are minority carriers and pentavalent atoms are dopants.
2. Holes are minority carriers and pentavalent atoms are dopants.
3. Holes are the majority carriers and trivalent atoms are dopants.
4. Electrons are the majority carriers and trivalent atoms are dopants.

Subtopic:  Types of Semiconductors |
 79%
From NCERT
AIPMT - 2013
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If a small amount of antimony is added to germanium crystal:
 
1. the antimony becomes an acceptor atom
2. there will be more free electrons than holes in the semiconductor
3. its resistance is increased
4. it becomes a \(p\small{-}\)type semiconductor

Subtopic:  Types of Semiconductors |
 82%
From NCERT
AIPMT - 2011
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Pure Si at \(500~\text{K}\) has an equal number of electron \((n_e)\) and hole\((n_h)\) concentrations of \(1.5\times10^{16}~\text{m}^{-3}\). Doping by indium increases \(n_h\) to \(4.5\times10^{22}~\text{m}^{-3}\).  The doped semiconductor is of:

1. \(p\)-type with electron concentration \(n_e=5\times10^9~\text{m}^{-3}\)
2. \(n\)-type with electron concentration \(n_e=5\times10^{22}~\text{m}^{-3}\)
3. \(p\)-type with electron concentration \(n_e=2.5\times10^{10}~\text{m}^{-3}\) 
4. \(n\)-type with electron concentration \(n_e=2.5\times10^{23}~\text{m}^{-3}\)
Subtopic:  Types of Semiconductors |
 76%
From NCERT
AIPMT - 2011
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Which one of the following statements is false?

1. Pure Si doped with trivalent impurities gives a p-type
semiconductor.
2. The majority of carriers in an n-type semiconductor are holes.
3. The minority carriers in a p-type semiconductor are electrons.
4. The resistance of intrinsic semiconductors decreases with an
increase in temperature.

Subtopic:  Types of Semiconductors |
 86%
From NCERT
AIPMT - 2010
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