# 867f09hw5 - K with the following: N A = 1E16 cm-3 = N D ; D...

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ELEG 867 - Devices for Light Detection from the Submillimeter to the Ultraviolet – Fall 2009 Homework #5 - due Friday, 9 October 2009, in class Photodetectors 1. Problem 4.3, from Rieke, p. 113. Hints: The detective quantum efficiency DQE is described on pp. 11 and 74, and includes the effects of noise; whereas Eqn. (4.24) just includes collection. 2. Calculate the gain and photocurrent density when 1 μ Watt of light with photon energy = 3 eV illuminates a photoconductor with η = 0.85, and minority carrier lifetime of 0.6 nsec. The electron mobility is 3000 cm 2 /V-s, the electric field is 5000 V/cm, and the device length = 10 μ m. 3. Calculate the steady state photocurrent density in a reversed biased long step junction pn photodiode at 300
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Unformatted text preview: K with the following: N A = 1E16 cm-3 = N D ; D n = 25 cm 2 /s; D p = 10 cm 2 /s; τ n = 0.5 μ s; τ p = 0.1 μ sec; the reverse bias is V F = -5 v, and the optical generation rate of EHPs is 10 21 cm-3-s-1 . The cross section area = A = 10-3 cm 2 . 4. In problem 3 above, consider that the photodiode is in series with a 5 K Ω resistor and biased by the 5 volt battery. Find the incident intensity of light at λ = 1 μ m such that the voltage across the load resistor is 0.5 volts. Homework assignments will appear on the web at: http://www.ece.udel.edu/~kolodzey/courses/eleg867f09.html. Note: On each homework and report submission, please give your name, the due date, assignment number and the course number....
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## This note was uploaded on 12/14/2011 for the course ELEG 687 taught by Professor Kolodzey during the Fall '09 term at University of Delaware.

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