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EESM5200 (L1) Quiz 01

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The effective density of states of a piece of silicon is ๐‘๐ถ=2โˆ—1019๐‘๐‘šโˆ’3 in the conduction band at room temperature and it is doped with both NA and ND.ย  Assume the intrinsic carrier concentration ๐‘›๐‘– is 1010๐‘๐‘šโˆ’3 and ND=1*1017๐‘๐‘šโˆ’3. Suppose 0.4% of the equivalent states in the conduction band are filled by electrons at room temperature. a) What is NA in the silicon per cm3? ย [Fill in the blank], b) What is the electron concentration in the silicon per cm3? ย [Fill in the blank], c) What is the hole concentration in the silicon per cm3? ย [Fill in the blank], d) What is the value of the Fermi-Dirac function ๐น๐‘’(๐ธ๐ถ) at the conduction band edge? ย [Fill in the blank],

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We begin by restating the problem to ensure clarity: a piece of silicon has Nc = 2 ร— 10^19 cm^-3, ni = 1 ร— 10^10 cm^-3, and is doped with both Na and Nd, with Nd = 1 ร— 10^17 cm^-3. The conduction-band states are 0.4% filled by electrons at room temperature. The questions ask for (a) Na, (b) electron concentration n, (c) hole concentration p, and (d) the value of the Fermi-Dirac function Fe(Ec) at the conduction-band edge. Option a) Na = 1.92 ร— 10^17 cm^-3 - This value is inconsistent with the charge-neutrality requirement once you determine n and p. To compute n from the stated conduction-band filling: 0.4% ......Login to view full explanation

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