Question

Pure Si at 300 K has equal electron `(n_(e))` and hole `(n_(h))` concentrations of `1.5xx10^(16)m^(-3)` doping by indium increases `n_(h)` to `4.5xx10^(22)m^(-3)`. Caculate `n_(e)` in the doped Si-
A. `9xx10^(5)`
B. `5xx10^(9)`
C. `2.25xx10^(11)`
D. `3xx10^(19)`

Answer 1

Correct Answer - B
In an extrinsic semiconductor,
`n_(e)n_(h)=(n_(i))^(2)`
`n_(e)xx4.5xx10^(22)=(1.5xx10^(16))^(2)`
`n_(e)=(2.25xx10^(32))/(4.5xx10^(22))n_(e)=5xx10^(9)`