When an arsenic atom is introduced in place of silicon in a crystal lattice, the conductivity.....
(a) increases
(b) decreases
(c) remains the same
(d) sometimes increases and sometimes decreases
listen .. answer with true specific reason
Answers
Explanation:
When a silicon crystal is doped with a group 15 elements such as P,As,Sb or Bi the structure of the crystal lattice is left unchanged but an occasional atom with five valence electrons occupies a site that would normally be occupied by a silicon atom.
The foreign atom uses four of its electrons in covalent bonding but the remaining fifth electron becomes delocalized and is thus free to contribute to electrical conduction.
Thus, both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
Option B is the answer.
Answer:
Because arsenic is pentavalent, it leaves one electron free when combined with silicon. In this instance, the conduction of electricity owing to electron mobility will rise.
Explanation:
When arsenic is introduced to silicon as an impurity, the resultant material is an n-type semiconductor.
An n-type semiconductor is an inherent semiconductor that has been impurity-doped with phosphorus (P), arsenic (As), or antimony (Sb).
Group IV silicon contains four valence electrons, whereas arsenic has five. When a trace quantity of arsenic is introduced to a silicon crystal, one of the ar's valence electrons becomes free to travel around the free electron as a surplus electron. Current flows when a free electron is attracted to the "+" electrode and moves.