In junction diode, the holes are due to

Options

A. protons
B. extra electrons
C. neutrons
D. missing eletrons

Answer

To solve the question "In junction diode, the holes are due to," we need to understand the concept of holes in semiconductor physics.

### Step-by-Step Solution:

1. **Understanding the Structure of Silicon:**
- Silicon (Si) is a semiconductor with four valence electrons. In its crystalline form, each silicon atom forms covalent bonds with four neighboring silicon atoms.

2. **Doping Silicon:**
- To create a p-type semiconductor, we introduce a trivalent impurity, such as aluminum (Al), into the silicon crystal. Trivalent means that aluminum has three valence electrons.

3. **Formation of Holes:**
- When aluminum is added to silicon, it forms bonds with three silicon atoms. However, since aluminum has only three valence electrons, it cannot form a bond with the fourth silicon atom. This results in a missing electron in the crystal structure.

4. **Concept of Holes:**
- The absence of an electron in the bonding structure is referred to as a "hole." Therefore, in a p-type semiconductor, holes are created due to the missing electrons that result from the trivalent doping.

5. **Conclusion:**
- In a junction diode, the holes are due to missing electrons created by the introduction of trivalent impurities (like aluminum) into the silicon crystal. Thus, the correct answer is "missing electrons."

### Final Answer:
The holes in a junction diode are due to missing electrons.

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