NEET Physics Semiconductor Electronics Questions Solved

A silicon speciman is made into a P-type semi-conductor by dopping, on an average, one Indium atom per 5×107 silicon atoms. If the number density of atoms in the silicon specimen is 5×1028 atoms/m3 then the number of acceptor atoms in silicon per cubic centimetre will be

(a) 2.5×1030 atoms/cm3                   (b) 1.0×1013 atoms/cm3
(c) 1.0×1015 atoms/cm3                   (d) 2.5×1036 atoms/cm3

(c) Number density of atoms in silicon specimen = 5×1028 atom/m3 = 5×1022 atom/cm3. Since one atom of indium is doped in 5×107 Si atom. So number of indium atoms doped per cm3 of silicon.

n=5×10225×107=1×1015 atom/cm3

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