Question

A silicon specimen is made into a `P`-type semiconductor by dopping, on an average, one helium atoms per `5xx10^(7)` silicon atoms. If the number density of atoms in the silicon specimen is `5xx10^(28) at om//m^(3)` then the number of acceptor atoms in silicon per cubic centimeter will be
A. `3xx10^15 "atom/cm"^3`
B. `1xx10^15 "atom/cm"^3`
C. `3xx10^18 "atom/cm"^3`
D. `1xx10^21 "atom/cm"^3`

Answer 1

Correct Answer - B
Indium atoms acts as acceptor atoms in p-type semiconductor.
No. of silicon atoms/`m^3=5xx10^28` atom/`m^3`
As `1 m^3 = 10^6 cm^3`
`therefore` No. of silicon atoms/`cm^3=(5xx10^28)/10^6`
`=5xx10^22` atoms/`cm^3`
`therefore` No. of indium atoms (acceptor atoms) in silicon `=(5xx10^22)/(5xx10^7) = 10^15` atoms/`cm^3`