Pure `Si` at `500K` has equal number of electron `(n_(e))` and hole `(n_(h))` concentration of `1.5xx10^(16)m^(-3)`. Dopping by indium. Increases `n_(h)` to `4.5xx10^(22) m^(-3)`. The doped semiconductor is of

Options

A. `n`-type with electrons concentration `n_(e)xx5xx10^(22)m^(-3)`
B. `p`-type with electrons concentration `n_(e)xx2.5xx10^(10)m^(-3)`
C. `n`-type with electrons concentration `n_(e)xx2.5xx10^(23)m^(-3)`
D. `p`-type with electrons concentration `n_(e)xx5xx10^(9)m^(-3)`

Answer

D

Explanation

`n_(i)^(2)=n_(h)n_(e) implies n_(e)=((n_(e))^(2))/(n_(h))`
`n_(e)=((1.5xx10^(16))^(2))/((4.5xx10^(22))) implies n_(e)=5xx10^(9) m^(-3)`
So, `n_(h)gt gt n_(e)` semiconductor is `p`-type.