Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 145 of 494
In semiconductor physics, what is the value of the forbidden energy band gap (\( E_g \)) for pure Silicon at room temperature (\( 300\text{ K} \))?
A
0.1 eV
B
0.7 eV
C
1.1 eV
D
6.0 eV
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: 1.1 eV
Concept:

The energy band gap \( E_g \) is the minimum energy required to excite an electron from the valence band to the conduction band.

Formula:

$$E_{g,\text{Silicon}} \approx 1.1\text{ eV} \quad \text{and} \quad E_{g,\text{Germanium}} \approx 0.7\text{ eV} \quad (\text{at } 300\text{ K})$$

Solution:

  • At room temperature, the energy band gap of crystalline Silicon is \( 1.12\text{ eV} \approx 1.1\text{ eV} \).


  • For Germanium, the band gap is \( 0.67\text{ eV} \approx 0.7\text{ eV} \).


Why other options are incorrect:

  • Option A: 0.1 eV is characteristic of narrow-gap semi-metals.
  • Option B: 0.7 eV is the bandgap of Germanium (and the barrier potential of Silicon in volts).
  • Option D: 6.0 eV is the bandgap of an insulator like diamond.

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