Hole is

Options

A. an anti-particle of electron
B. a vacancy created when an electron leaves a covalent bond
C. absence of free electrons.
D. an artificially created particle.

Explanation

To answer the question "What is a hole?" in the context of semiconductor physics, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Definition of a Hole**: A hole is defined as the absence of an electron in a semiconductor material. When an electron is excited from its normal position (such as in a covalent bond), it leaves behind a vacancy, which is termed a hole.

2. **Formation of a Hole**: Holes are created when an electron leaves its covalent bond. This can happen due to thermal energy or when the material is doped with impurities that provide energy to the electrons.

3. **Characteristics of Holes**: Holes can be thought of as positive charge carriers in a semiconductor. They behave as if they are positively charged because the absence of a negatively charged electron creates a net positive charge in that location.

4. **Comparison with Electrons**: While electrons are negatively charged and can move freely in the conduction band, holes represent the absence of electrons and can also move through the lattice structure of the semiconductor, effectively allowing for the conduction of electricity.

5. **Conclusion**: Therefore, the correct answer to the question is that a hole is a vacancy created when an electron leaves a covalent bond. This is the most accurate description among the provided options.

### Final Answer:
A hole is a vacancy created when an electron leaves a covalent bond.

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