Question

With increase in temperature in an intrinsic semi-conducter, the ratio of conduction electrons and holes is

• A. $1:1$
• B. $1:2$
• C. $2:1$
• D. $1:3$

Answer 1

Answer: (A)

$1:1$

For the intrinsic semiconductors, $n=p=ni$.

Where, $n$ represents the number of electrons and $p$ represents the number of holes and $ni$ represents the number of charge carriers in intrinsic semiconductors.
If the temperature is increased, the covalent bonds will break and electrons will be freed. Each electron will leave behind a hole and capture a new hole the process will continue and equal numbers of electrons and holes will be present in intrinsic semiconductors again, i.e.,
$n^{\prime }=p^{\prime }=ni$
Hence, the ratio $n:p$ = $n^{\prime }:p^{\prime }=1:1$.