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# Homework_5 - Ω-cm at T = 300K. a.) What is the donor...

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EE338 Physical Electronics Homework Assignments #5 Prof. Steve Cronin Due Feb. 25, 2010 Carrier Transport: 1. The electron mobility of a semiconductor material is μ n and the hole mobility is μ p at some temperature. Calculate the intrinsic conductivity of the material at that temperature. What is the minimum conductivity of the material at that temperature? 2. a.) A silicon semiconductor is in the shape of a rectangular bar with a cross sectional area of 10 μ m x 10 μ m, a length of 0.1 cm and is doped with 5 x 10 16 cm - 3 arsenic atoms. The temperature is T = 300K. Determine the current if 5V is applied across the length of the bar. B) Repeat part a.) if the length is reduced to 0.01 cm. c.) Calculate the average drift velocity of electrons in parts a.) and b.). 3. An n-type silicon sample has a resistivity of 5
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Unformatted text preview: Ω-cm at T = 300K. a.) What is the donor impurity concentration? B.) What is the expected resistivity of the material at T = 200K and T = 400K? 4. Two scattering mechanisms exist in a semiconductor. If only the first mechanism were present the mobility of the semiconductor would be 250 cm 2 / V-s. If only the second mechanism were present the mobility would be 500 cm 2 /V-s. What is the mobility when both mechanisms are present? 5. The electron density in a semiconductor decreases linearly from 10 16 cm-3 to 10 15 cm-3 over a distance of 0.1 cm. The electron diffusion coefficient is 25 cm 2 /s. Calculate the electron diffusion current density. 6. Problem 4.41 in Neamen. 7. Problem 4.45 in Neamen. 8. Problem 4.51 in Neamen....
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## This note was uploaded on 04/04/2010 for the course EE 338 taught by Professor Dapkus during the Spring '07 term at USC.

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