1. Define doping. 2. What is the difference between a pentavalent atom and a trivalent atom? 3. What are other names for the pentavalent and trivalent atoms? 4. How is an n-type semiconductor formed? 5. How is a p-type semiconductor formed? 6. What is the majority carrier in an n-type semiconductor? 7. What is the majority carrier in a p-type semiconductor? 8. By what process are the majority carriers produced? 9. By what process are the minority carriers produced? 10. What is the difference between intrinsic and extrinsic semiconductors?

Doping is the process of adding impurities to an intrinsic semiconductor to alter its properties. The impurities added are of a different valency than the semiconductor, thus providing either extra free electrons or creating holes.

A pentavalent atom is an atom that has five valence electrons in its outermost shell, while a trivalent atom has three valence electrons.

Pentavalent atoms are also known as donor atoms because they donate free electrons. Examples include phosphorus (P), arsenic (As), and antimony (Sb). Trivalent atoms are also known as acceptor atoms because they accept free electrons. Examples include boron (B), gallium (Ga), and indium (In).

An n-type semiconductor is formed by doping an intrinsic semiconductor with a pentavalent impurity. The extra valence electron from the pentavalent atom is loosely bound and can easily move around, contributing to the current.

A p-type semiconductor is formed by doping an intrinsic semiconductor with a trivalent impurity. The trivalent atom creates a hole, or absence of an electron, which can move around the lattice and contribute to the current.

The majority carrier in an n-type semiconductor is the electron.

The majority carrier in a p-type semiconductor is the hole.

The majority carriers are produced by the doping process. In an n-type semiconductor, the pentavalent impurity atoms donate their extra electron. In a p-type semiconductor, the trivalent impurity atoms accept an electron, creating a hole.

The minority carriers are produced by thermal generation. This is when an electron gains enough energy from heat to jump from the valence band to the conduction band, leaving a hole behind.

Intrinsic semiconductors are pure semiconductors with no impurities. They have an equal number of free electrons and holes. Extrinsic semiconductors are doped semiconductors. They have an imbalance of free electrons and holes, with one type being the majority carrier and the other being the minority carrier.