GATE Electronics and Communications (EC) 2022 Solved Paper
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Consider a long rectangular bar of direct bandgap p-type semiconductor. The equilibrium hole density is 1017 cm-3 and the intrinsic carrier concentration is 1010 cm-3 . Electron and hole diffusion lengths are 2 μm and 1 μm, respectively.
The left side of the bar (x = 0) is uniformly illuminated with a laser having photon energy greater than the bandgap of the semiconductor. Excess electron-hole pairs are generated ONLY at x = 0 because of the laser. The steady state electron density at x = 0 is 1014 cm-3 due to laser illumination. Under these conditions and ignoring electric field, the closest approximation (among the given options) of the steady state electron density at x = 2 μm, is ___________ .
The left side of the bar (x = 0) is uniformly illuminated with a laser having photon energy greater than the bandgap of the semiconductor. Excess electron-hole pairs are generated ONLY at x = 0 because of the laser. The steady state electron density at x = 0 is 1014 cm-3 due to laser illumination. Under these conditions and ignoring electric field, the closest approximation (among the given options) of the steady state electron density at x = 2 μm, is ___________ .
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