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Unformatted text preview: of the electron. 5. (a) Explain why holes are found at the top of the valence band, whereas electrons are found at the bottom of the conduction band. (b) Explain why Si doped with 10 14 cm-3 Phosphorous is n-type at 400 K but similar doped Ge is not. 6. Si sample is doped with 6 X 10 15 cm-3 donors and 2 X 10 15 cm-3 acceptors. Find the position of the Fermi level with respect to E i at 300 K. 7. Solar cell problem: Fig 1 shows the solar spectral irradiance area (unit: W/m 2 nm) vs different wavelengths (unit: nm). Please calculate the percentage of the sun’s power that will be absorbed into the silicon. (Assume Eg=1.24eV)....
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- Winter '10
- Condensed matter physics, Practice Problem Set, Fermi energy, Prof. B. Jalali, electron state