On doping `Ge` with a little of `In or Ga` one gets

Options

A. p-type semiconductor
B. insultor
C. n-type semiconductor
D. rectifier

Explanation

To solve the question regarding the doping of germanium (Ge) with indium (In) or gallium (Ga), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Doping**: Doping is the process of adding impurities to a semiconductor to change its electrical properties. In this case, we are doping germanium (Ge).

2. **Identifying the Doping Elements**: The elements mentioned for doping are indium (In) and gallium (Ga). Both of these elements belong to Group 13 of the periodic table.

3. **Valency of Doping Elements**: Indium and gallium are trivalent, meaning they have three valence electrons. When they are introduced into the germanium lattice, they will replace some of the germanium atoms.

4. **Formation of Holes**: Germanium has four valence electrons. When a trivalent atom (like In or Ga) replaces a tetravalent germanium atom, it forms a bond with three of the surrounding germanium atoms but leaves one bond incomplete. This creates a "hole," which can be thought of as a positive charge carrier.

5. **Type of Semiconductor**: The presence of these holes increases the number density of positive charge carriers (holes) compared to negative charge carriers (electrons). Therefore, the semiconductor formed by doping germanium with indium or gallium is classified as a p-type semiconductor.

6. **Conclusion**: Thus, when germanium is doped with a small amount of indium or gallium, it results in the formation of a p-type semiconductor.

### Final Answer:
When doping germanium (Ge) with a little of indium (In) or gallium (Ga), one gets a p-type semiconductor.

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