SOLUTION

An n-type semiconductor is electrically neutral.

• In an n-type semiconductor, current conduction is due to an excess of electrons but these extra electrons were supplied by the atoms of donor impurity and each atom of donor impurity is electrically neutral.
• When the impurity atom is added, the term “excess electrons” refers to excess with regard to the number of electrons needed to fill the covalent bonds in the semiconductor crystal.
• The n-type semiconductor thus formed remains electrically neutral, i.e., neither positively charged nor negatively charged. This is because the total number of electrons including the free electrons is equal to the total number of protons in the nuclei of the atoms.