ELEG 340: Solid-State Electronics, Fall 2008
Homework #6 - due Tuesday, 28 October 2008, at the beginning of class
1. Problem 4.17, p. 151 of Streetman-Banerjee, 6th edition. Hint: Eqn. (4-44) does not include
recombination, so you must multiply by the e-t/τ factor. Easiest to use a ratio of the two times.
2. Problem 5.7 (a) only; for NA = 1014 cm-3 only, and for the ND’s listed, do the odd numbered
exponents only.
3. Problem 5.9, p. 243 of Streetman-Banerjee, 6th edition.
4. Problem 5.10, p. 243 of Streetman-Banerjee, 6th edition. Hint: to find xno and xpo, first find
Wdep and then use the doping ratio factors.
5. Problem 5.12, p. 243 of Streetman-Banerjee, 6th edition.
6. Problem 5.14 (a) only, p. 243 of Streetman-Banerjee, 6th edition. Hints: by “junction
capacitance”, they mean what we call “depletion capacitance”. To find φbi; first find φn on the n-
side from ND, and then assume that φp on the p-side is just (Ei-Ev)/q, i.e. just half the bandgap
voltage, which is a good approximation for a p+ region. Then find Wdep for this built-in potential
and the given reverse bias.
Homework assignments will appear on the web at:
http://www.ece.udel.edu/~kolodzey/courses/eleg340f08.html
Note: On each homework and report submission, please give your name, the due date,
assignment number and the course number.