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A p-type semoconductor has acceptor leve...

A p-type semoconductor has acceptor levels `57meV `above the valence band. Find the maximum wavelength of light which can create a hole.

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To create a hole, an electron form the valence band should be hiven sufficient erergy to go into one of the acceptor levels. Since the acceptor levels are `57meV`above the valence band, at least `57meV`is needed to create a hole.
If `(lambda)`be the wevelength of light, its photon will have an energy `hc/(lembda)`.to create a hole,
`(hc/(lambda))le57meV`
or,`(lembda)le(hc)/(57meV)`
(1242eV nm)/(57xx10^(-3)eV)=2.18xx10^(-5)m`.
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