Question

The INCORRECT statement is

• A. The lattice structure of Ge is called diamond like structure
• B. The number of electrons in the outermost orbit of Si is 4
• C. The energy band gap of semiconductors is less than 3 eV
• D. The number of free electrons is equal to number of holes in Ge
• E. The energy band gap of Ge is greater than 4 eV

Hint:

Key band gaps to remember at 300K:
Silicon (Si) \(\approx 1.1 \text{ eV}\).
Germanium (Ge) \(\approx 0.7 \text{ eV}\).
Gallium Arsenide (GaAs) \(\approx 1.4 \text{ eV}\).

Answer 1

Answer: (E)

Step 1: Understanding the Concept:
Semiconductors like Germanium (Ge) and Silicon (Si) have specific electronic and physical properties that distinguish them from conductors and insulators.

Step 3: Detailed Explanation:
Evaluate each statement:
- Option A: Both Ge and Si crystallize in a diamond cubic lattice structure. (True)
- Option B: Si is a Group 14 element and has 4 valence electrons. (True)
- Option C: Semiconductors are defined by a narrow energy band gap, typically less than 3 eV. (True)
- Option D: In an intrinsic (pure) semiconductor like Ge, every electron that jumps to the conduction band leaves a hole in the valence band, so \(n_e = n_h\). (True)
- Option E: The energy band gap of Ge is actually about 0.67 eV at room temperature. A gap greater than 4 eV would characterize an insulator, not a semiconductor. (False)

Step 4: Final Answer:
The incorrect statement is that the energy band gap of Ge is greater than 4 eV.