Nature of bonding in a semiconductor is

The correct answer is Option (4) → Covalent

In semiconductors such as silicon and germanium, each atom has four valence electrons and shares one with each of its four nearest neighbours. These shared electron pairs are covalent bonds, which hold the crystal together.

NCERT (2026-27):
Intrinsic Semiconductor – “… We know that Si and Ge have four valence electrons. In its crystalline structure, every Si or Ge atom tends to share one of its four valence electrons with each of its four nearest neighbour atoms, and also to take share of one electron from each such neighbour. These shared electron pairs are referred to as forming a covalent bond or simply a valence bond.”