Question

A $Si$ specimen is made into p-type semiconductor is made into by doping on an average one indium atom per $6\times {10}^7$ silicon atoms. If the number density of atoms in $Si$ be $6\times {10}^{28}/m^3$, what is the indium atoms per ${cm}^3$?

• A. ${10}^{12}$
• B. ${10}^{15}$
• C. ${10}^{18}$
• D. ${10}^{20}$

Answer 1

The correct option is B ${10}^{15}$

The doping of one indium atom in silicon semiconductor will produce one acceptor atom in p-type semiconductor.
Now, 1 indium atom has been dopped per $6\times {10}^7$ silicon atoms,

So number density of acceptor atoms in silicon is $=\frac{6\times {10}^{28}}{6\times {10}^7}={10}^{21}atoms/m^3={10}^{15}atoms/c{m}^3$