314-SampleProblems-F201000005 - It m ay be assum ed, as a...

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It may be assumed, as a rough approximation, that the hole and electron mobilities both G vary as T and that the bandgap E is independent of temperature. -3/2 (a) Sketch a suitable activation energy plot (relating D to inverse temperature), verify its G. linearity and hence determine the value of E (b) At w hat w avelength w ould you expect the onset of optical absorption for Ge? 9. Figure show s a cylindrical bar of an intrinsic G semiconductor of energy gap E = 1.0 eV and e electron affinity O = 5.0 eV. The bar is 1 cm long and has an area of cross-section of 0.01 cm . The contacts at A and B are ohmic. Assume 2 equal effective densities of states in the c v conduction and valence bands: N = N = 10 20 cm . -3 (a) Sketch approximately to scale the energy- band diagram (Electron energy E vs. distance x) of the semiconductor in thermal vac equilibrium, clearly labeling the relative locations of the vacuum level E , the c v F conduction band edge E , the valence band edge E , and the Fermi level E . AB
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This note was uploaded on 10/16/2010 for the course E SC 314 at Penn State.

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