Concept:The potential barrier is the built-in potential difference across the depletion region at thermal equilibrium that opposes the diffusion of majority charge carriers.
Formula:$$V_B(\text{Si}) \approx 0.7\text{ V}, \quad V_B(\text{Ge}) \approx 0.3\text{ V} \quad (\text{at } T = 300\text{ K})$$
Solution:- Silicon has a bandgap energy of approximately \( 1.1\text{ eV} \).
- At room temperature (\( 300\text{ K} \)), the resulting built-in barrier potential across a standard silicon junction is approximately \( 0.7\text{ V} \).
- For comparison, germanium has a smaller bandgap (\( 0.67\text{ eV} \)) and a barrier potential of \( 0.3\text{ V} \).
Why other options are incorrect:- Option A: \( 0.1\text{ V} \) is significantly below the barrier potential of common elemental semiconductors.
- Option B: \( 0.3\text{ V} \) is the potential barrier of a germanium (\( \text{Ge} \)) diode at room temperature.
- Option D: \( 1.1\text{ V} \) represents the energy bandgap (\( E_g \)) of silicon in electron-volts (\( 1.1\text{ eV} \)), not its junction barrier voltage.
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