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Chemistry / Re: While electrons in the band gap is there no wavelength, or frequency to move
« on: 25/05/2016 13:41:35 »No. The band gap is between energy levels. Electrons can be below the band gap, and then moved above the band gap, but will never be in the gap (hence the word "gap"). The span of the gap determines how much energy is required, and glass has a large band gap, so therefore requires photons with high energies.What will happen if photons with slightly higher energy than required by the band gap hit the electrons?
Usually (for hard matter) there is a fairly broad band that the electron can get excited to above the band gap, so there will be a broad absorption starting at the band gap energy, and extending to higher energies. There can be a second band gap that prevents absorption at specific range of higher energies. Eventually when the energy of the photon is high enough, it can be absorbed and cause an electron to leave the material completely (photoelectric effect).
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