The energy gaps (E_g) between valence band and conduction band for...

The energy gaps

\left(E_g\right)

between valence band and conduction band for diamond, silicon and germanium are in the order

Options

A $E_g$ (diamond) $>E_g$ (silicon) $>E_g$ (germanium)
B $E_g$ (diamond) $< E_g$ (silicon) $< E_g$ (germanium)
C $E_g$ (diamond) $=E_g\left(\right.$ silicon) $=E_g$ (germanium)
D $E_g$ (diamond) $>E_g$ (germanium) $>E_g$ (silicon).

Correct answer

A. $E_g$ (diamond) $>E_g$ (silicon) $>E_g$ (germanium)

Step-by-step solution

Semiconductors are solids where there is only a small difference in energy, called a 'band gap', between the filled valence band of electrons and a conduction band.

\begin{array}{lc}\text{ Compound } & \left.\text{ Energy gap (kJ } \mathbf{J} \mathbf{ m o l}^{-\mathbf{1}}\right) \\ \text{ Diamond } & 579 \\ \text{ Silicon } & 106 \\ \text{ Germanium } & 68\end{array}

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