Question

A silicon specimen is made into a p-type semiconductor by doping on an average one indium atom per $5\times {10}^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5\times {10}^{28}$ atom/ $m^3$ , then the number of acceptor atoms in silicon per cubic centimeter will be

• A. $2.5\times {10}^{30}atom/c{m}^3$
• B. $2.5\times {10}^{35}atom/c{m}^3$
• C. $1.0\times {10}^{13}atom/c{m}^3$
• D. $1.0\times {10}^{15}atom/c{m}^3$

Answer 1

Answer: (D)

Number density of atoms in silicon specimen $=5\times {10}^{28}atom/m^3$ $=5\times {10}^{22}\text{ atom/c}{\text{m}}^{\text{3}}$ Since, 1 atom of indium is doped in $5\times {10}^7$ silicon atoms, so total number of indium atoms doped per $c{m}^3$ of silicon will be $n=\frac{5\times {10}^{22}}{5\times {10}^7}$ $={10}^{15}\text{atom/c}{\text{m}}^{\text{3}}$