EL ENG 130 Midterm: ee130-sp2008-mt1-Hu-soln
Document Summary
There are 12 pages of this exam including this page. [5pts] (a) draw qualitatively the fermi-dirac distribution at t=300k, t=150k, and. [10pts] (b) quantum wells are often used in applications such as semiconductor lasers. In a quantum well, electrons are confined in a thin slab of material, as shown below. The density-of-states, d(e) in an ideal quantum-well is step-like: At t 0k, there are 1. 4 105 states in this system, mark the location of fermi. Level, ef? (in this problem, there is no need to consider spin explicitly since it is already taken into account in d(e). ) At 0k, all the states below ef are filled with electrons; all the states above. Ec f e d e de v i. This means the number of electrons in the system, n, equals the area under the. D(e) curve up to ef, times the volume of the semiconductor, v.
