To prepare n-typesemi conductor the impurity to be added to silicon should have which number of valence electrons and why - Chemistry -

Question

To prepare n-typesemi conductor the impurity to be added to silicon
should have which number of valence electrons and why

Akanksha · Accepted Answer

↵To
prepare n-type semiconductor , the impurity to be added to silicon
should have five valence electrons

we know that Si has
valency of 4 Now when a pure semiconductor like Si in which each
atom has 4 valence electrons, is doped with a controlled amount of
pentavalent atoms like Antimony, which have 5 valence electrons,
the impurity atom replaces a Si atom and 4 out of the 5 electrons
form covalent bonds by sharing the electrons with the adjoining 4
toms of Si while the fifth electron is free to move hence
constituting the current in the semiconductor Since this type of
semiconductor has free electrons to donate, it is also called donor
type semiconductor