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The ratio of number density of free elec...

The ratio of number density of free electrons to holes for two different materials, A and B, are (i) equal to one and (ii) less than one respectively. Name the type of semiconductor to which A and B belong. Draw energy level diagram for A and B.

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`n_(e)/n_(h) = 1 rArr n_(e) = n_(h) therefore` Intrinsic semiconductor
`n_(e)/n_(h) lt 1 rArr n_(e) lt n_(h) therefore` p type extrinsic semiconductor.
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