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 $\left(E_{q}\right)_{ Ge }$ respectively. Which one of the following relationships is true in their case?

• A. $\left(E_{g}\right)_{C}>\left(E_{g}\right)_{S i}$
• B. $\left(E_{g}\right)_{C}=\left(E_{g}\right)_{S i}$
• C. $\left(E_{g}\right)_{ C }
• D. $\left(E_{g}\right)_{C}>\left(E_{g}\right)_{S i}$

Answer 1

Answer: (D)

$\left(E_{g}\right)_{C}>\left(E_{g}\right)_{S i}$

Answer 2

Carbon, silicon and germanium are semiconductors. $\left(E_{g}\right)_{C}=5.2\, eV$ $\left(E_{g}\right)_{S i}=1.21\, eV$ $\left(E_{g}\right)_{ Ge }=0.75\, eV$ Thus, $\left(E_{g}\right)_{C}>\left(E_{g}\right)_{S i}$ and $\left(E_{g}\right)_{C}>\left(E_{g}\right)_{G e}$ Elements carbon, silicon and germanium are found in IVA group of periodic table.