The number of silicon atoms per `m^(3)` is ` 5 xx 10^(28)`. This is doped simultaneously with `5 xx 10^(22)` atoms per `m^(3)` of Arsenic and `5 xx 10^(20)` per `m^(3)` atoms of Indium. Calculate the number of electrons and holes given that `n_(i) = 1.5 xx 10^(16) m^(-3)`. Is the material n-type or p-type?

Explanation

Arsenic is pentavalent and Indium is trivalent.
`n_(e) = 5 xx 10^(22) - 0.05 xx 10^(22) = 4.95 xx 10^(22)`
but `" "n_(i)^(2) = n_(e)n_(h)`
`therefore " "n_(h) = (2.25 xx 10^(22))/(4.95 xx 10^(22)) = 0.454 xx 10^(10)`
`n_(h) = 4.54 xx 10^(9) `per `m^(3)`
since `n_(e) gt n_(h)`, the material is n type.