The value indicated by fermi-energy level in an intrinsic semiconductor is

Options

A. The average energy of electrons and holes
B. The energy of electrons in conduction band
C. The energy of holes in valence band
D. The energy of forbidden region

Answer

To determine the value indicated by the Fermi energy level in an intrinsic semiconductor, we can follow these steps:

### Step 1: Understand the Concept of Fermi Energy Level
The Fermi energy level is a crucial concept in semiconductor physics. It represents the energy level at which the probability of finding an electron is 50%. In intrinsic semiconductors, which are pure and undoped, the Fermi level is positioned between the valence band and the conduction band.

**Hint:** Recall that the Fermi level indicates the energy distribution of electrons at absolute zero temperature.

### Step 2: Identify the Structure of Intrinsic Semiconductors
Intrinsic semiconductors have a characteristic band structure consisting of a valence band filled with electrons and a conduction band that is empty at absolute zero. The energy gap between these two bands is known as the forbidden energy gap.

**Hint:** Visualize the band structure of intrinsic semiconductors to understand where the Fermi level lies.

### Step 3: Analyze the Position of the Fermi Level
In an intrinsic semiconductor, the Fermi level is located exactly in the middle of the valence band and the conduction band. This positioning indicates that the concentration of electrons in the conduction band is equal to the concentration of holes in the valence band.

**Hint:** Consider how the equal concentration of electrons and holes affects the Fermi level's position.

### Step 4: Determine the Value Indicated by the Fermi Energy Level
Since the Fermi level is positioned in the middle of the conduction band and the valence band, it can be interpreted as the average energy of the electrons and holes present in the semiconductor.

**Hint:** Think about what it means for the Fermi level to represent an average energy in a system with equal numbers of electrons and holes.

### Conclusion
The value indicated by the Fermi energy level in an intrinsic semiconductor is the average energy of electrons and holes. Therefore, the correct answer is:

**Option 1: The average energy of electrons and holes.**