ECE 874: Physical Electronics

1
ECE 874Physical Electronics

• Prof. Virginia Ayres
• Electrical Computer Engineering
• Michigan State University
• ayresv_at_msu.edu

2
Lecture 06, 18 Sep 12
3
Heat hydrogen gas, get atomic hydrogen (not H2)
1 proton 1 electron.
Atomic hydrogen can only radiate or absorb energy
in discreet packets En -13.6 eV/n2, n 1, 2,
3, This formula can also be used as an
approximation for systems that are like hydrogen,
such as excitons.
4
Quantization of angular momentum Ln m0vrn
nhbar, n 1, 2, 3,
Charge Coulomb force
Motion Centripetal force
Eliminate v, get expression for rn in terms of
integer n
5
Now get an expression for total energy En
Energy due to motion
Get v in terms of rn from force balance (not L
quantization). Reason thats how PE is written.
Energy due to charge
Now substitute for rn on previous slide to get En
in terms of integer n
6
(No Transcript)
7
(No Transcript)
8
This is the predicated ground state energy
level. What you can observe are transitions,
e.g., E2 E1
9
(No Transcript)
10
http//www.matter.org.uk/diffraction/geometry/geom
etry_of_diffraction_braggs_law_2.htm
11
(No Transcript)
12
(No Transcript)
13
Chp. 02 3 important examples of electron showing
wavelike properties

• Free electron
• An electron between scattering events during
  transport in a semiconductor is often nearly free
• Motivation low heat transisotrs
• Electron in an infinite potential well
• Electron in a finite potential well
• Pr. 2.7 Electrons in a triangular well
  realistic
• Motivation these are all about Quantum well
  lasers
• Arai article
• http//ieeexplore.ieee.org/stamp/stamp.jsp?tpar
  number4265925
• Transitions between quantized energy levels DE
  hc/l what you see is light of precise
  wavelength l

14
Approach conservation of energy applied to
wavelike electrons
15
Approach conservation of energy applied to
wavelike electrons/particles
16
Approach conservation of energy applied to
wavelike electrons
17
Approach conservation of energy applied to
wavelike electrons