Question

In germanium crystal, the forbidden energy gap in joule is:

• A. $1.6\times {10}^{-19}$
• B. zero
• C. $1.12\times {10}^{-19}$
• D. $1.76\times {10}^{-19}$

Answer 1

Answer: (C)

$1.12\times {10}^{-19}$

For $Ge,E_g=0.7eV=0.7\times 1.6\times {10}^{-19}J=1.12\times {10}^{-19}J$. Germanium in the crystalline form has an energy gap between the valence band and conduction band. However, the pure intrinsic semiconductor can be converted into the p-type and n-type semiconductor.

Trivalent impurities if added to germanium then it forms the p-type semiconductor whereas if pentavalent impurities are added then it forms the n-type semiconductor.