Question

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (E_g)_C, (E_g)_Si and (E_g)_Ge. Which of the following statements is true?

Options

• (E_g)_Si < (E_g)_Ge < (E_g)_C

• (E_g)_C < (E_g)_Ge > (E_g)_Si

• (E_g)_C > (E_g)_Si > (E_g)_Ge

• (E_g)_C = (E_g)_Si = (E_g)_Ge

Answer 1

(E_g)_C > (E_g)_Si > (E_g)_Ge

Explanation:

Of the three given elements, the energy band gap of carbon is the maximum and that of germanium is the least.

The energy band gap of these elements are related as: (E_g)_C > (E_g)_Si > (E_g)_Ge