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Unformatted text preview: o C). 4. A silicon sample is doped with 10 17 As atoms/cm 3 . The intrinsic free electron concentration in Si at room temperature is 3 10 10 5 . 1 cm . (A) What is the equilibrium hole concentration p at 300K? (B) Sketch the position of the Fermi level in the band gap. 4. Below, the intrinsic electrical conductivity of a semiconductor at two temperatures is tabulated: [Useful relations: h e e p e n + = ; ( ) kT E N n g c 2 exp = ; 1 kT =26 meV at 298K]. ( a ) Determine the band gap energy (in eV) for this material. Answer: _____________________ ( b ) Estimate the electrical conductivity at 298 K. Answer:______________________ Sample question for ChE 350 Spring 2010 Quiz 10 Name:________________________ 2 (c) In the band diagram shown below, sketch the Fermi level position for this semiconductor. (D) Sketch qualitatively the Fermi level in the band gap for this Si sample at 1000K....
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