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

Answer

For solar cell, incident photon energy must be greater than band gap energy, i.e, (hv > Eg) For GaAs, Eg = 1.43eV = 1.43eV and high optical absorption $\approx$ 104 cm–1, which are main criteria for fabrication of solar cells.

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