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B3C053S Pages: 3

Reg. No. Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
THIRD SEMESTER B.TECH DEGREE EXAMINATION, JULY 2017

EC203: SOLID STATE DEVICES (AE, EC)

Max. Marks:100. Duration: 3 Hours

PART A
Answer any One from Qn. No.2 and 3. Qn. No. 1 is Compulsory.

1. a) Plot the Fermi Dirac distribution function versus Energy for different temperatures. Justify

the plot using necessary equations. (5)
b) Show that ‏مآ‎ is the average distance an electron diffuses before 1! recombines. (5)
c) Derive the expression for conductivity of a Semiconductor. (5)

. a) For the given data, calculate hole and intrinsic carrier concentrations. Also sketch the

band diagram. Nc= 101775, Ny= 5510 ला, ಗೃ-20%, T=900°K, ‏احم‎ 0! ला (5)
b) Define Hall Effect. Derive the expressions for i) majority carrier concentration ii)
mobility. (5)
0) Prove that the minimum conductivity of a semiconductor occurs when no= 1(|५ / Lin)’.

Also find the expression for minimum conductivity. (5)

OR

3. a) A p-type Si with minority electron lifetime of 0.1൮, is uniformly illuminated by a light

having photon energy of 2.5eV.
i) Determine the rate of excess carrier generation that is required to generate a uniform
electron concentration 081019 ണ്‌. (2)

ii) What is the optical power (जा) that should be absorbed to create the excess carrier

population of part (i)? (2)
iii) How much optical power per സേ will be generated if the carriers recombine via
photoemission? (2)
b) Derive Steady state diffusion equations. (6)
c) State and explain the different recombination mechanisms. (3)

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