University of California, Berkeley
EE230 - Solid State Electronics
Prof. J. Bokor
FINAL PROBLEM SET
(Due 4:00PM, Monday, May 19, 2008)
Turn in at my office (508 Cory) on or before 4PM sharp on Monday, May 19, 2008. Late
papers will not be graded.
Take home, open book. You may consult any sources you wish, however, only results from class
notes, the two textbooks (
Introduction to Solid State Physics, 8th edition,
by Charles Kittel, and
Fundamentals of Carrier Transport,
by M. Lundstrom, either edition), or standard references
(integral tables, physical constants, etc.) may be cited without derivation.
You must work strictly
individually. No collaboration with anyone else, either in or out of this class is permitted.
Violation of this rule will be considered to be an incident of cheating on an exam. See the
Academic Dishonesty link on the class web page.
If there are any important corrections or other announcements necessary during the period of the
exam, I will post them on the class web site. Please check it periodically. I will do my best to
respond in a timely fashion to questions about the exam that are emailed to me.
Consider electron impact ionization in a semiconductor, where a single high-energy electron
loses energy by creating an electron-hole pair. If the initial kinetic energy of the electron is
(the band-gap energy), then the final state in an impact ionization process would have
two electrons and one hole, all at rest.
a) Show that, in this case, momentum is not conserved.