HW #1
ECE 404
Spring 2012
Due: Aug 29
1. What is the energy of the photons associated with
a. ray, = 0.008
b. X-ray, = 2
c. ultraviolet, = 0.2 m
d. infrared, = 4 m
2. Metal with a work function = 2 V. What is the energy of
the emitted electrons from the
0HW#5
ECE404
Fall 2015
Due: Oct 6
1) (a) Calculate the drift velocity, vd, of electrons in a semiconductor with n =
1000 cm2/Vs and an electric field of 4 kV/cm.
= = (1000 2 )(4000 ) = 4.0 106 /
(b) Compare this to the thermal velocity of a free electron
ECE 404
Fall 2015
HW #9
Due: Nov. 24
1. Find the maximum depletion width, maximum capacitance Ci and the
threshold voltage for an ideal MOS capacitor with a 10 nm gate oxide
(SiO2) on p-type Si with Na=21016 cm-3.
2 1016 3
= 2 = 2(0.0259 )
= 0.731
1.5
ECE 404
Fall 2015
HW #7
Due: Nov 3
1. A Si p-n junction has pp = 5 1017 and nn = 2 1016 cm-3, = 400 and
= 600 cm2/Vs, =10-7 s and = 10-5 s and A = 10-4 cm2.
a) Find and .
= (0.0259 )(400 2 ) = 10.4 2
=
= (0.0259 )(600 2 ) = 15.5 2
=
= = (10.
HW#3
ECE404
Fall 2015
Due: Sept. 15
1) For a metal what is the probability, f(E), for an electron located at room
temperature at an energy level i) 30 meV ii) 2 eV above the Fermi level EF.
i)
1
() =
1 + ()/
1
=
= 0.239
1 + 0.030 0.0259
ii)
1
() =
1 + ()
HW #1
ECE 404
Fall 2015
Due: Sept. 1
1. Show that for photons, the wavelength and the energy E are
related as:
1.24
in micrometers, E in eV
E
=
=
34
(6.626 10 )(2.998 108 )
= =
=
25
1.986 10 106
1
=
1 1.602 1019
1.24
=
2. What is the energy of th
HW#4
ECE404
Fall 2015
Due: Sept. 22
1) Estimate ni of pure GaN at i) 77 K and ii) 1000 C given ni=2103 cm-3 at 300
K. Assume Nc and Nv dont depend upon temperature.
= 3.4
= /2
(2 ) /22 /22
=
=
(1 ) /21 /21
i) 77 K
2
77
= 0.0259
= 0.00665
1
300
/
/
ECE404
I)
2- 0
4)
0
2-0
5) l
/6/
(7/1/
2.) 2-D
~) 2-
Fall 2015
10
tJ
(~ (/o/:;j
( S-;-tf1 J
5- u.-v'"
Test II
1,
a) Draw the band diagram (EF, E" E" etc.) for a p-n junction with:
i) Zero bias
ii) Forward bias
iii) Reverse Bias
b) Show by derivation tha
HW #2
ECE 404
Fall 2015
Due: Sept 8
1. An electron in the conduction band combines with a hole in
the valence band in an intrinsic semiconductor. Find the
wavelength (in nm) and their color of emitted light (UV,
blue, green, red, IR etc.) due to this tran
ECE 404
Fall 2015
HW #8
Due: Nov. 17
1. Light with an intensity of 100 mW/cm2 is incident on a semiconductor
slab 2 m thick with an absorption coefficient = 8103 cm-1. Find
a) the intensity of the transmitted light
= 0
3
1
4
= (100 2 ) (810 )(210 ) = 20