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Quantum Tunneling

  • Thread starter fredrick08
  • Start date
  • #1
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Homework Statement


A 10eV electron is incident on a potential barrier of height 25eV and width 1nm. Estimate (order of magnitude) the probability that the electron will tunnel through the barrier, repeat your calculations for a barrier of 01.nm

Homework Equations


T=16(E/V)(1-(E/V))exp(-2[tex]\alpha[/tex]a)
[tex]\alpha[/tex]=[tex]\sqrt{}(2m(V-E))[/tex]/[tex]\hbar[/tex]


The Attempt at a Solution


E=10eV=1.6x10^-18J, V=25eV=4x10^-18J

[tex]\alpha[/tex]=[tex]\sqrt{}(2*9.1x10^-31(4x10^-18-1.6x10^-18))[/tex]/6.62x10^-34=3.157x10^9

T=3.84exp(-2*3.157x10^9*1x10^-9)=7x10^-3???

the answer is meant to be 9.2x10^-9 or 4.95x10^-13???? sorry, my book says 4.95 and the lecturers notes say 9.2... doesnt matter, coz im way way off...

please can someone help me where i am going wrong?
 

Answers and Replies

  • #2
376
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sorry about the latex the x is multiply
 
  • #3
376
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plz anyone?
 
  • #4
Matterwave
Science Advisor
Gold Member
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Well, the only thing I see is that instead of hbar you used h in your calculations. hbar is a factor of 2pi smaller than h.
 
  • #5
376
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omg oops, thanks
 
  • #6
376
0
still have wrong answer, anyone know y?
 

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