ps02 - samples are illuminated with light which generates...

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1 MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Electrical Engineering and Computer Science 6.012 ELECTRONIC DEVICES AND CIRCUITS Problem Set No. 2 Issued: September 12, 2003 Due: September 19, 2003 Reading Assignments: Lecture 2 (9/9/03) - Chap. 3 (all except 3.3.2 ), App. B Note change (italicized) Lecture 3 (9/11/03) - Chap. 4 (all) Lecture 4 (9/16/03) - Chap. 5 (all) Lecture 5 (9/18/03) - Chap. 6 (all) Lecture 6 (9/23/03) - Chap. 7 (7.1,7.2) Lecture 7 (9/25/03) - Chap. 7 (7.3, 7.4.1a) Problem 1 - Do Problem 3.13 in the course text. Problem 2 - Do Problem 5.7 in the course text. Note: Part (a)(i) should read “. .. R will decay as. ..” Problem 3 - This question concerns the two samples illustrated below. Both are n-type silicon samples with a net donor concentration, N D , of 10 16 cm -3 ; electron mobility, µ e , of 1600 cm 2 /V-s; hole mobility, µ h , of 600 cm 2 /V-s; and minority carrier lifetime, t min , of 10 -6 s. One bar, Sample A, is 2 µm long; the other, Sample B, is 22 µm long. Both
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Unformatted text preview: samples are illuminated with light which generates qM hole-electron pairs cm-3-s-1 uniformly across the plane at x = 1µm. M n Ohmic Sample A n Sample B M Ohmic Ohmic x (µm) 22 1 2 a) What are the minority carrier diffusion coefficient, D h , and the minority carrier diffusion length, L h , in these samples? b) Sketch the excess minority carrier profiles in the two samples. Assume L h >> 22 µm, inspite of what you may have calculated in Part (a). You need not calculate p'(1 µm). 2 c) i) In Sample A, what fraction of the injected hole-electron pairs recombine at the ohmic contact at x = 0? ii) In Sample B, what fraction of the injected hole-electron pairs recombine at the ohmic contact at x = 0? d) In which sample, A or B, if any, is p'(1 µm), the excess hole concentration at x = 1 µm, larger? Explain your answer. Problem 4 - Do Problem 5.2 in the course text. Problem 5 -Do Problem 5.9 in the course text....
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This note was uploaded on 03/24/2010 for the course ARCH 456 taught by Professor Arch during the Spring '10 term at MIT.

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ps02 - samples are illuminated with light which generates...

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