If we mix a trivalent impurity in the crystal lattice of germinium the type of semiconductor formed will be:

Options

A. p-type
B. n-type
C. both (a) and (b)
D. None of the two

Explanation

To determine the type of semiconductor formed when a trivalent impurity is mixed into the crystal lattice of germanium, we can follow these steps:

### Step-by-Step Solution

1. **Identify the Element**:
- Germanium (Ge) is a group 14 element in the periodic table.

2. **Understand the Impurity**:
- A trivalent impurity means that the impurity atom has three valence electrons. This impurity will typically come from group 13 elements (e.g., Boron, Aluminum).

3. **Doping Process**:
- When a trivalent impurity is introduced into the germanium lattice, it replaces some of the germanium atoms. Since germanium has four valence electrons, the trivalent impurity will create a deficiency of one electron.

4. **Creation of Holes**:
- The absence of an electron creates a "hole," which can be thought of as a positive charge carrier. This hole can accept an electron from a neighboring atom, allowing for the movement of charge within the semiconductor.

5. **Charge Carrier Movement**:
- As electrons move to fill these holes, the holes themselves can move through the lattice. This movement of holes contributes to electrical conductivity.

6. **Type of Semiconductor**:
- Since the majority charge carriers in this scenario are holes (positive charge carriers), the semiconductor formed is classified as a **p-type semiconductor**.

7. **Conclusion**:
- Therefore, the type of semiconductor formed when a trivalent impurity is mixed in the crystal lattice of germanium is a **p-type semiconductor**.

### Final Answer
The correct answer is: **p-type semiconductor**.