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(i). In an unbiased p-n junction, why holes diffuse from the p- region to n- region?(ii). A p-n junction is fabricated from a semiconductor with band gap of 2.8 eV. Can it detect a wavelength of 600 nm? |
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Answer» (i). In an unbiased p-n junction, Holes diffuse from the p- region to n- region because hole concentration in p-region is more as compared to n- region. (ii). Energy, E = \(\frac{hc}{\lambda}\) = \(\frac{6.6\times10^{-34}\times 3 \times 10^8}{600\times 10{-9}\times 10^{-19}}\)eV = 2.06 eV As E< Eg (2.8 eV), So p-n junction cannot detect the radiation of given wavelength. |
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