20082ee2_1_Midterm08 - ElectricalEngineeringDepartment...

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-END-. . . . . . . . . . . . . . . . . . . EE2 Midterm (Open Book and Notes) I. Silicon has a diamond structure with a lattice constant of 5.43 angstroms (The length of the edge of the conventional unit cell). (a) Draw a silicon conventional unit cell. Show the tetrahedral feature of the structure. (8 %) (b) Show the atomic configuration of the silicon. How to form the tetrahedral bonds? (7%) (c) How many silicon atoms do you have in a 1 3 mm cube of silicon crystal? (5%) (d) How many silicon atoms do you have in a spherical shell of silicon crystal with a radius of 1cm and a thickness of 1 m µ ? (5%) II. InP has a zinc blende structure (like GaAs) with a lattice constant of 5.87 angstroms, an energy gap of 1.35 eV, and an electron effective mass of 0.08 0 m , a hole effective mass of 0.85 0 m , where 0 m is the free electron mass. (a) How many phosphorus atoms do you have in a 1 3 mm cube of InP crystal? (5%) (b) Find out the photon wavelength of a laser made of InP. Is it visible? (5%) (c) Find out the curvature of the conduction band of InP at the band edge. (5%)
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This note was uploaded on 04/13/2010 for the course EE ee2 taught by Professor Unknown during the Spring '10 term at UCLA.

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