Pure silicon dopend with phosphorus is a

Options

A. metallic conductor
B. n - type semiconductor
C. p - type semiconductor
D. insulator

Answer

To solve the question "Pure silicon doped with phosphorus is a", we need to understand the concepts of intrinsic and extrinsic semiconductors, as well as the effect of doping with different types of impurities.

### Step-by-Step Solution:

1. **Understanding Pure Silicon**:
- Pure silicon (Si) is a semiconductor that belongs to group 14 of the periodic table. In its pure form, it has four valence electrons and is classified as an intrinsic semiconductor.

**Hint**: Remember that intrinsic semiconductors are pure materials without any impurities.

2. **Doping Process**:
- Doping is the process of adding impurities to a semiconductor to change its electrical properties. There are two types of dopants:
- **Trivalent (Group 13)**: These elements have three valence electrons (e.g., Aluminum, Gallium). Doping with these creates "holes" and results in a p-type semiconductor.
- **Pentavalent (Group 15)**: These elements have five valence electrons (e.g., Phosphorus, Arsenic). Doping with these adds extra electrons, resulting in an n-type semiconductor.

**Hint**: Doping with trivalent elements creates holes (p-type), while doping with pentavalent elements adds extra electrons (n-type).

3. **Identifying the Dopant**:
- In this case, we are doping pure silicon with phosphorus, which is a pentavalent element. This means that phosphorus will provide an extra electron to the silicon lattice.

**Hint**: Identify the type of dopant to determine the resulting semiconductor type.

4. **Determining the Type of Semiconductor**:
- Since phosphorus is a pentavalent dopant, the extra electron it contributes results in an n-type semiconductor. This is because the additional electron increases the negative charge carriers (electrons) in the material.

**Hint**: Remember that n-type semiconductors have more electrons than holes.

5. **Conclusion**:
- Therefore, pure silicon doped with phosphorus is classified as an n-type semiconductor.

**Final Answer**: Pure silicon doped with phosphorus is an **n-type semiconductor**.