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The energy of a photon of sodium ligh...

The energy of a photon of sodium light `( lamda = 589 nm)` equal to the band gap of a semiconducing material .
Find the minimum energy E required to create a hole -electron pair.

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The energy of the photon in eV =`( 12400 )/(lamda)`
Wavelength of photon = 589 nm `= 5890 A^0`
`=(12400)/( 5890 ) = 2.1 eV `
Thus the band gap is 2.1 eV. This is also the minimum energy E required to push an electron from the valence band into the conduction band. Hence, the minimum energy required to create a hole-electron pair is 2.1eV.
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AAKASH SERIES-SEMICONDUCTOR DEVICES-EXAMPLES
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