Question

what is n- type and p- type semiconductor

Answer 1

In a pure (intrinsic) Si or Ge semiconductor, each nucleus uses its four valence electrons to form four covalent bonds with its neighbors (see figure below). Each ionic core, consisting of the nucleus and non-valent electrons, has a net charge of +4, and is surrounded by 4 valence electrons. Since there are no excess electrons or holes In this case, the number of electrons and holes present at any given time will always be equal.

Answer 2

Hey !!

Question = What is a n-type semiconductor and p-type semiconductor ?

ANSWER :- N- TYPE SEMICONDUCTOR ==>When silicon or germanium crystal is doped with a GROUP - 5 element like P or As the dopant atom forms 4 covalent bonds like a Si or Ge atom but the 5th electron, not used in bonding, becomes delocalised and contributes its share towards electrical conduction. Thus, silicon or germanium doped with P or As is called N-TYPE SEMICONDUCTOR, therefore n indicates negative charge of electron since it is the electron that conducts electricity.

P - TYPE SEMICONDUCTOR ==> When silicon or germanium is doped with a group 13 element like B or Al, the dopant atom forms 3 covalent bonds , but at the place of fourth electron a hole is created. This hole moves through the crystal like a positive charge giving rise to electrical conductivity. Thus , Si or Ge doped with B or Al is called p-type semiconductor ( P stands for +ve hole ), since it is the +ve hole that is responsible for conduction.

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