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Question
In a pure semiconductor, the number of conduction election 6 × 1019 per cubic metre. How many holes are there in a sample of size 1 cm × 1 mm?
Solution
Pure semiconductors are intrinsic semiconductors or semiconductors without any doping.
We know that for pure semiconductors, the number of conduction electrons is equal to the number of holes.
Number of electrons in volume 1 m3 = 6 × 1019
Number of holes in volume 1 m3 = 6 × 1019
Given volume:
V = 1 cm × 1 cm × 1 mm
\[\Rightarrow\] V = 1 × 10−2 × 1 × 10−2 × 10−3
Number of holes in volume 10-7 m3 .
N = 6 × 1019 × 10−7 = 6 × 1012
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