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}}\text{ }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}}} $