Introduction to Semiconductors: Intrinsic and Extrinsic

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Questions and Answers

In an N-type semiconductor, what are the majority carriers?

Electrons

What type of semiconductor is produced when boron is added to a pure germanium crystal?

P-type

What happens to the fifth electron of an antimony atom in an N-type semiconductor?

It is easily excited to the conduction band

What is the effect of adding an acceptor impurity to pure germanium?

It increases the number of positive holes Signup and view all the answers

What are thermally-generated charge carriers also known as?

Intrinsically-available charge carriers Signup and view all the answers

What is the defining characteristic of a semiconductor material?

It has an energy gap of about 1 eV Signup and view all the answers

What is the energy gap of pure silicon, an intrinsic semiconductor?

1.1 eV Signup and view all the answers

At what temperature do intrinsic semiconductors have many electrons that can jump across the small energy gap between the valence and conduction bands?

Room temperature Signup and view all the answers

What happens when impurities are added to intrinsic semiconductors in extremely small amounts?

They become extrinsic or impurity semiconductors Signup and view all the answers

How can extrinsic semiconductors be classified based on the type of doping material used?

N-type and P-type Signup and view all the answers

Match the following semiconductor types with their majority carriers:

N-type Extrinsic Semiconductor = Electrons P-type Extrinsic Semiconductor = Holes Signup and view all the answers

Match the following impurity elements with the type of semiconductor they produce:

Antimony (Sb) = N-type Extrinsic Semiconductor Boron (B) = P-type Extrinsic Semiconductor Signup and view all the answers

Match the following semiconductor materials with their primary usage:

Germanium = Base material for extrinsic semiconductors Silicon = Intrinsic semiconductor Signup and view all the answers

Match the following charge carriers with the type of semiconductor they are associated with:

Majority of positive holes = P-type Extrinsic Semiconductor Majority of electrons = N-type Extrinsic Semiconductor Signup and view all the answers

Match the following energy bands with the charge carriers they are associated with:

Valence band = Holes Conduction band = Electrons Signup and view all the answers

Match the following semiconductor types with their characteristics:

Intrinsic semiconductor = Made of extremely pure semiconductor material Extrinsic semiconductor = Contains impurity or doping agent in small amounts N-type semiconductor = Doped with material that provides extra conduction electrons P-type semiconductor = Doped with material that creates holes in the crystal lattice Signup and view all the answers

Match the following energy bands with their corresponding descriptions:

Conduction band = Almost empty band where charge carriers can move freely Valence band = Almost filled band where electrons are tightly bound to atoms Energy gap = Narrow gap separating the conduction and valence bands Forbidden energy gap = Small energy gap of the order of 1 eV in semiconductors Signup and view all the answers

Match the following elements with their corresponding intrinsic semiconductors:

Germanium = Forbidden energy gap of 0.72 eV Silicon = Forbidden energy gap of 1.1 eV Antimony = Not an intrinsic semiconductor Boron = Not an intrinsic semiconductor Signup and view all the answers

Match the following characteristics with their corresponding extrinsic semiconductors:

N-type semiconductor = Extra conduction electrons due to specific impurity doping P-type semiconductor = Presence of holes in the crystal lattice due to specific impurity doping Boron-doped semiconductor = Belongs to the category of extrinsic semiconductors Silicon-doped semiconductor = Belongs to the category of extrinsic semiconductors Signup and view all the answers

Match the following temperature ranges with their corresponding behavior of intrinsic semiconductors:

Room temperature = Many electrons possess sufficient energy to jump across the small energy gap Very low temperature = Minimal conductivity due to lack of thermally-generated charge carriers High temperature = Increased thermal excitation leading to more charge carriers Signup and view all the answers