When a piece of pure silicon is doped with aluminium, then
the conductivity of the doped silicon piece will remain the same
the doped silicon piece will become n-type
the doped silicon piece will become p-type
the resistivity of the doped silicon piece will increase
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-1 – 2017
Pure silicon is a semiconductor with a valence of four. Aluminium is a Group 13 element and acts as a trivalent impurity (valence of three) when doped into silicon. When a trivalent impurity replaces a silicon atom in the crystal lattice, it creates a ‘hole’ (absence of an electron) in the covalent bond structure. These holes act as positive charge carriers, making the doped semiconductor p-type.