N type semiconductors have excess electrons or holes ?

Question

Answer

Electrons are the majority carriers of n typ semiconductor whereas holes are the majority carriers of p type semiconductor.

Answer

Electrons are the majority carriers of n type semiconductor whereas holes are the majority carriers of p type semiconductor.

Answer

Electrons

Answer

N-type semiconductors have excess electrons.

N-type semiconductors are formed by adding impurities to the pure semiconductor material, usually by doping with elements from Group V of the periodic table, such as phosphorus or arsenic. These impurities are called donor impurities because they donate extra electrons to the semiconductor crystal structure.

Donor impurities
- Donor impurities have five valence electrons, one more than the four valence electrons of the atoms in the pure semiconductor material (Group IV elements like silicon or germanium).
- When a donor impurity atom is incorporated into the crystal lattice of the semiconductor material, the extra electron becomes loosely bound and can move freely within the crystal structure.
- At room temperature, some of the donor impurity atoms ionize, releasing the extra electron into the conduction band of the semiconductor.

Excess electrons
- The presence of these extra electrons in the conduction band gives rise to an excess of negative charge carriers, known as free electrons.
- These free electrons are responsible for the electrical conductivity of the N-type semiconductor.
- Due to thermal energy, the free electrons move randomly within the crystal lattice, creating an electron current when an electric field is applied.

Effect on conductivity
- The presence of excess electrons in the N-type semiconductor increases its conductivity.
- The free electrons can easily move through the crystal lattice, contributing to the flow of electric current.
- The higher the concentration of donor impurities, the greater the number of excess electrons and thus the higher the conductivity of the N-type semiconductor.

Conclusion
In summary, N-type semiconductors have excess electrons due to the incorporation of donor impurities from Group V elements. These excess electrons increase the conductivity of the semiconductor and are responsible for its electrical properties.

Similar Class 12 Doubts

The densities of electrons and holes in an extrinsic semiconductor are 8 x 1015cm-3and 5 x 1012cm-3respectively. The mobilities of electrons and holes are respectively 23 x 103cm3/ Vs and 102cm3/ Vs. Which type of semiconductor is it?

Select the correct statement(s).

When n-type semiconductor is heated [1989]

One or More than One Options Correct TypeThis section contains 5 multiple type questions. Each question has 4 choices (

In a n-type semiconductor, which of the followingstatement is true? [NEET 2013]

Top Courses for Class 12

Suggested Free Tests

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams