Why are Si and GaAs are preferred materials for solar cells?

Explanation

**Step-by-Step Solution:**

1. **Definition of Solar Cells:**
- Solar cells are electronic devices that convert solar energy (sunlight) directly into electrical energy. This process is known as the photovoltaic effect.

2. **Materials Used in Solar Cells:**
- The two most commonly used materials for solar cells are Silicon (Si) and Gallium Arsenide (GaAs).

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