Question

Carbon, silicon and germanium have four valence electrons each. These are characterized valence and conduction bands separated by energy band gap respectively equal to ${{(Eg)}_{C}},{{(Eg)}_{Si}}$ and ${{(Eg)}_{Ge}}$ . Which of the following statements is true?

• A. ${{(Eg)}_{C}}={{(Eg)}_{Si}}={{(Eg)}_{Ge}}$
• B. ${{(Eg)}_{C}}>{{(Eg)}_{Si}}>{{(Eg)}_{Ge}}$
• C. ${{(Eg)}_{C}}{{(Eg)}_{Si}}$
• D. ${{(Eg)}_{Si}}{{(Eg)}_{C}}$

Answer 1

Answer: (B)

${{(Eg)}_{C}}>{{(Eg)}_{Si}}>{{(Eg)}_{Ge}}$

Answer 2

Carbon , germanium (Ge) and silicon (Si) are semiconductros. They lie in 1VA group of periodic table.
${{(Eg)}_{C}}=5.2eV$ ${{(Eg)}_{Ge}}=0.75eV$
${{(Eg)}_{Si}}=1.21eV$
Thus, it is obvious that
${{(Eg)}_{C}}>{{(Eg)}_{Si}}>{{(Eg)}_{Ge}}$