State the reason, why GaAs is most commonly used in making of a solar cell.

Gallium arsenide (GaAs) is commonly used in making solar cells for several reasons:

1. Efficiency: GaAs solar cells offer higher conversion efficiencies compared to traditional silicon solar cells. This is because GaAs has a narrower bandgap, allowing it to absorb a broader spectrum of light, including infrared wavelengths, which are not efficiently absorbed by silicon.

2. High Absorption Coefficient: GaAs has a high absorption coefficient, meaning it can absorb more photons within a shorter distance compared to silicon. This allows for the fabrication of thinner solar cells, reducing material usage and cost.

3. Temperature Stability: GaAs solar cells perform better at high temperatures compared to silicon solar cells. They have a lower temperature coefficient, meaning their efficiency decreases less with increasing temperature, making them suitable for applications in hot climates or environments.

4. Durability: GaAs is more resistant to radiation damage, making GaAs solar cells more suitable for use in space applications where they are exposed to high levels of radiation.

5. Flexibility: GaAs solar cells can be grown using various techniques, including epitaxial growth, which allows for the fabrication of thin, lightweight, and flexible solar cells. This flexibility is advantageous for applications such as space exploration missions and portable electronic devices.

Overall, the unique properties of GaAs make it an  material for solar cell applications, particularly in situations where high efficiency, durability, and temperature stability are crucial.