F2010_ECE132_Quiz5_Wed

F2010_ECE132_Quiz5_Wed - ): What will the depletion region...

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ECE 132 Quiz 5 Name _________________________ November 10, 2010 1) Consider a pn junction where both the p and n regions are heavily doped by the same amount (N A ++ = N D -- = 10 20 cm -3 ). In this case, the Fermi level is essentially at the band edge, E F E v on p side; E F ≈ E c on n side. What will the approximate value of W be in this case? a) Infinity (Width of the semiconductor) b) ~5 cm c) Zero What will the built in voltage, V bi be? a) 0.7 V b) 0 V c) E c E v = E g 2) Now consider a p-i-n structure which has an intrinsic, undoped region in between the p and n regions. If both the p and n regions are heavily doped by the same amount (N A ++ = N D -- = 10 20 cm -3
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Unformatted text preview: ): What will the depletion region widths, W n and W p , be relative to the pn junction? a) The same as the widths of the p-n junction (x no =W n , x po = W p ) b) Less than the depletion widths of the p-n junction(W n <x no , W p <x po ) c) Greater than the depletion widths of the p-n junction (W n >x no , W p >x po ) What will the built in voltage be? a) 0.7 V b) 0 V c) E c E v = E g Notes: W n & W p : Depletion region widths. W = W i + W n + W p is the region over which V bi is sustained NOT drawn to any scale NOT drawn to any scale L= 10 cm W n W p W i = 100 m i P N P N x no x po L= 10 cm W...
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This note was uploaded on 12/06/2010 for the course ECE 132 taught by Professor Denbaars during the Fall '08 term at UCSB.

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