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Why are Si and GaAs preferred materials for solar cells ? Explain. |
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Answer» Solution :The solar radiation received by us on earth is as shown in . From the FIGURE, it is clear that maximum solar intensity corresponds to energy of about 1.5 eV. For photo excitation energy of incident radiation (E = hv) should be S greater than the ener8y band gap `E_(s)` for given semiconductor. Hence, semiconductor with band gap of~1.5 eV or lower is likely to GIVE better solar conversion efficiency. As silicon has band gap of 1.1 eV and GaAs a band gap of 1.53 eV, hence these materials are preferred for solar cells. Out of Si and GaAs we prefer GaAs, INSPITE of its higher band gap energy value, because its absorption COEFFICIENT is relatively higher. ` ` |
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