# 0.19 Even semester2014-midsemester examination answers  (Page 2/3)

1. XIV. What does the above Table refer to ? Describe the meaning of the terms entered in the boxes ? Answer: The angle between the Primary Flat of the Si Wafer and the Secondary Flat of the Si Wafer is ‘α’. Type tells if Si-Wafer is N-Type or P-Type. Orientation gives the cleavage plane Orientation in Miller Indices.[1/6+1/6+1/6=1/2Point]

XV. What do the different terms refer to in the above Integral Equation? Answer: N(E)=density of states per unit volume per unit energy, P(E) →Fermi-Dirac Statistics or the probability of occupancy at energy E by Fermions. dE → elemental energy, m*→effective mass of electron in the conduction band.X 0 →Fermi Level in Metal with respect to the bottom edge of the Conduction Band i.e.X 0 =E F - E C .[1/10+1/10+1/10+1/10+1/10=1/2 Points]

XVI.

In the adjacent equation and in Question XV, X 0 is the same parameter. What is this parameter. Answer: X 0 =E F - E C .[1/2 Point]

XVII.

What are the different parameters and what are their units ? Answer: E g is Band-Gap in eV and λ is the wavelength of the photon emitted accompanying the radiative transition from Conduction Band to the Valence Band.[1/4+1/4=1/2]

XVIII. Define the parameters and give the units ?

Semiconductor E g n i ε r (DC) ? ρ i (300K) N C N V
Si 1.12 1×10 10 11.7 5×10 22 /cc 3.2×10 5 3.2×10 19 /cc 1.8×10 19 /cc
Ge 0.67 2×10 13 16.2 4.4×10 22 /cc 48 1×10 19 /cc 5×10 18 /cc
GaAs 1.424 2.1×10 6 12.9 4.42×10 22 /cc 3.3×10 8 4.7×10 17 /cc 7×10 18 /cc

Answers: E g (eV) , n i (#/cc), ε r (DC) rel.permittivity (Dimensionless ), #density of atoms in the crystal , ρ i (300K) Intrinsic Resistivity in Ω-cm, N C _ Effective Density of States at E C, N V _ Effective Density of States at E V [1/14+1/14+1/14+1/14+1/14+1/14+1/14=1/7]

XIX.

Define the terms and give the units. v = 10 7 cm/s. What is this velocity. Answers: v drift = electric drift velocity(m/s), μ(mobility) (cm 2 /(V-s)), q=electric charge(Coulombs), τ scattering (Mean Free Path or Relaxation Time)(sec),m* e =effective mass of electron(Kg)[1/28,1/28,1/28,1/28,1/28,1/28,1/28, 1/28,1/28,1/28,1/28,1/28,1/28,1/28,=1/2]

XX.

This rule is called Matthiessen’s Rule. Define the parameter and give the units of the parameter. Answers:μ effective ,→ effective mobility, μ imp ,→mobility due to impurity scattering, μ lattice ,→mobility due to lattice scattering, cm 2 /(V-s), [1/8+1/8+1/8+1/8=1/2]

XXI.

What are these power laws. Answers: lattice scattering inverse 3/2 power law , impurity scattering 3/2 power law [1/4+1/4=1/2 points]

XXII. σ = qμn Define the terms and give the units. Answers: σ →conductivity(Siemens/cm), q→electronic charge(Coulomb),μ→mobility(cm 2 /(V-s),n→conducting electron number density[1/16+1/16+1/16+1/16+1/16+1/16+1/16+1/16=1/2 Points]

XXIII. What special information is given by this Table.

Metal Au Cu Ni Pt
Effective Mass/Free Mass of electron 1.1 1.01 28 13

Answers: Ni and Pt are heavy Fermionic Metals [1/4+1/4=1/2]

XXIV. What is the basic difference about electron transport reflected by the Table below ?

Element E F τ(femtosec) L(Angstrom) W F v e 1 (×10 5 m/s)
Li 4.7 9 90 9.96
Na 3.1 31 250 2.3 8.08
K 2.1 44 293 2.2 6.55
Cu 7.0 27 328 12.15
Ag 5.5 41 441.6 10.77
Ge E V +E G /2 2217 2106 1.16
Si E V +E G /2 767.6 729 1.16
GaAs E V +E G /2 4890 4645.5 1.16

explain and give four Example hyperbolic function
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Abdullahi
hi mam
Mark
find the value of 2x=32
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
yes i wantt to review
Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
how do we prove the quadratic formular
Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
thank you help me with how to prove the quadratic equation
Seidu
may God blessed u for that. Please I want u to help me in sets.
Opoku
what is math number
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
x+2y-z=7
Sidiki
what is the coefficient of -4×
-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Jeannette has \$5 and \$10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
What is the expressiin for seven less than four times the number of nickels
How do i figure this problem out.
how do you translate this in Algebraic Expressions
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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