ECE131_2008SPRING_EXAM1__[0]

# ECE131_2008SPRING_EXAM1__[0] - Electrical Engineering...

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" Electrical Engineering Dcpartmenl The Cooper Union, ECE 131A Solid-Slale Materials & Devices Examination 1/ Spring 2008 1. A semiconductor materia! Z has the energy band model shown in the figure below. The material Z has fl j = IO lo /cm3, E e 0:: 1.12eV and kT = O.025geV at room temperatme. - - E, ;- __ ------------~ E. : I x • -(1I2) x-o I x • L{2 a) Determine whether equilibrium conditions within the material Z exist, or no!. b) Det.ennine the majority and minority carrier concentrations at x ;::: -(Lj4), x . . 0 and x = (L/4). c) Determine the range of values for x, if any exist, for the material Z will be degenerate. d) Give an appropriately labeled sketch for the electrostatic potential V(x). e) Give an appropriately Jabeled sketch for the electric field E(x). (20%) 2. The Fermi energy level for material X al T = 300K is 6.25eV. The electrons iII this material are detennined by Ihe Fermi-Dirac distribution function. kT = O.025geV al T = 300K. a) Calculate the probability of an energy level at 6.50eV being occupied by an electron at room tenlperalllre.

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## This note was uploaded on 02/27/2012 for the course CHEMISTRY/ CH/ECE/PH/ taught by Professor Faculty during the Spring '08 term at Cooper Union.

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ECE131_2008SPRING_EXAM1__[0] - Electrical Engineering...

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