Pure silicon is doped with a small amount of PHOSPHORUS (a pentavalent element from group 15). The resulting semiconductor is

1. NCERT §14.4 explains doping: a PENTAVALENT impurity (P, As, Sb) contributes ONE extra valence electron per atom to the silicon lattice (Si is tetravalent — group 14). 2. The fifth electron is loosely bound and easily released into the conduction band, even at room temperature. 3. The result is a semiconductor with MANY more electrons than holes — electrons are the MAJORITY carriers and holes are the MINORITY carriers. This is the n-TYPE semiconductor. 4. (The 'n' refers to the negative charge of the majority carriers; the material itself remains electrically neutral overall, because each donated electron leaves behind a fixed positive ion at the donor site.) 5. Option A would require equal carrier numbers (intrinsic, which doping breaks). Option B is p-type (created with trivalent dopants like boron). Option C is wrong — doping makes the semiconductor MORE conducting, not less. _Source: NCERT Class 12 Physics Part 2, Ch 14, §14.4 (Extrinsic Semiconductor — (i) n-type), p. 7._