In intrinsic semiconductor at room temperature, the number of electrons and holes are

Options

A. unequal
B. equal
C. infinite
D. zero

Answer

To solve the question regarding the number of electrons and holes in an intrinsic semiconductor at room temperature, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Intrinsic Semiconductors**:
- An intrinsic semiconductor is a pure semiconductor material without any significant dopant atoms present.
- Examples include silicon (Si) and germanium (Ge).

2. **Behavior at Absolute Zero (0 Kelvin)**:
- At 0 Kelvin, intrinsic semiconductors behave like insulators.
- There are no free charge carriers (electrons or holes) because all electrons are in the valence band, forming covalent bonds.

3. **Behavior at Room Temperature (300 Kelvin)**:
- As the temperature increases to room temperature (approximately 300 Kelvin), thermal energy allows some electrons to gain enough energy to break free from their covalent bonds.
- This process creates electron-hole pairs: when an electron jumps from the valence band to the conduction band, it leaves behind a hole in the valence band.

4. **Equal Number of Electrons and Holes**:
- In intrinsic semiconductors, the number of electrons (n) in the conduction band is equal to the number of holes (p) in the valence band.
- This is due to the fact that for every electron that is excited to the conduction band, a corresponding hole is created in the valence band.

5. **Conclusion**:
- Therefore, at room temperature, the number of electrons (n) is equal to the number of holes (p) in an intrinsic semiconductor.

### Final Answer:
In an intrinsic semiconductor at room temperature, the number of electrons is equal to the number of holes.