Tetra valent semiconductor is to be doped with ______ valent element to achieve _____ type extrinsic semiconductor.

Options

A. penta, n
B. tri, p
C. penta, p
D. both (A) and (B)

Explanation

To solve the question, we need to understand the concepts of doping in semiconductors and the types of extrinsic semiconductors that can be formed.

### Step-by-Step Solution:

1. **Identify the Type of Semiconductor**:
- A tetravalent semiconductor has four valence electrons. Common examples include silicon (Si) and germanium (Ge).

2. **Understand Doping**:
- Doping is the process of adding impurities to a semiconductor to change its electrical properties.

3. **Determine the Doping Element**:
- If we dope a tetravalent semiconductor with a trivalent element (which has three valence electrons), it creates an excess of holes (positive charge carriers). This type of semiconductor is called a **p-type** semiconductor.
- If we dope a tetravalent semiconductor with a pentavalent element (which has five valence electrons), it creates an excess of electrons (negative charge carriers). This type of semiconductor is called an **n-type** semiconductor.

4. **Fill in the Blanks**:
- Therefore, the tetravalent semiconductor is to be doped with a **trivalent** element to achieve a **p-type** extrinsic semiconductor.
- Alternatively, it can be doped with a **pentavalent** element to achieve an **n-type** extrinsic semiconductor.

5. **Final Answer**:
- Tetravalent semiconductor is to be doped with **trivalent** element to achieve **p-type** extrinsic semiconductor.
- Tetravalent semiconductor is to be doped with **pentavalent** element to achieve **n-type** extrinsic semiconductor.