Question

Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by $\left(E_{g}\right)_{C},\left(E_{g}\right)_{S i}$ and $\left(E_{g}\right)_{G e}$ respectively. Which one of the following relationships is true in their case?

• A. $(E_g)_C > (E_g)_{Si}$
• B. $(E_g)_C = (E_g)_{Si}$
• C. $(E_g)_C < (E_g)_{Si}$
• D. $(E_g)_C \ne (E_g)_{Si}$

Answer 1

Answer: (A)

Carbon, silicon and germanium are semiconductors. $\left(E_{g}\right)_{C}=5.2 \,eV$
$ \left(E_{g}\right)_{S i}=1.21 \,eV$
$\left(E_{g}\right)_{S i}=1.21 \,eV$
Thus, $\left(E_{g}\right)_{S i}=1.21\, eV$
and $\left.\left(E_{g}\right)_{C}>E_{g}\right)_{G e}$
Note: Elements carbon, silicon and germanium are found in $IV$A group of periodic table.