Contact potential versus temperature

Discussion in 'Homework Help' started by xxxyyyba, Nov 13, 2013.

  1. xxxyyyba

    Thread Starter Member

    Aug 7, 2012
    249
    2
    Hi!
    Here is my task:
    Concentration of donor atoms on N side is Nd=10^17 cm^(-3) and concentration of acceptor atoms on P side is 2*10^15 cm^(-3). Construct a plot in Matlab of contact potential versus temperature, on same graph, for these models:
    Eg(T)=Eg0, Eg(T)=Eg0-a*T and Eg(T)=Eg0-(alfa*T^2)/(beta+T).
    k=8.62*10^(-15)eV, Eg0=0.785eV, alfa=7.02*10^(-4) eV/K, beta=1108K, a=3.66*10^(-4) eV/K, C=1.76*10^16.

    Here is my code:
    T=1:800;
    Na=2*10^15;
    Nd=10^17;
    k1=1.38*10^(-23);
    k=8.62*10^(-5);
    C=1.76*10^16;
    alfa=7.02*10^(-4);
    beta=1108;
    a=3.66*10^(-4);
    q=1.602*10^(-19);
    Eg0=0.785;
    Egtlinearni=Eg0-a.*T;
    Egtnelinearni=Eg0-(alfa.*T.^2)./(beta+T);
    Egtpriblizno=Eg0;
    figure
    nilinearni=sqrt(C.*T.^3.*exp(-Egtlinearni./(k.*T)));
    ninelinearni=sqrt(C.*T.^3.*exp(-Egtnelinearni./(k.*T)));
    nipriblizno=sqrt(C.*T.^3.*exp(-Egtpriblizno./(k.*T)));
    Vcplinearni=(k1.*T./q).*log((Na.*Nd)./(nilinearni.^2));
    Vcpnelinearni=(k1.*T./q).*log((Na.*Nd)./(ninelinearni.^2));
    Vcppriblizno=(k1.*T./q).*log((Na.*Nd)./(nipriblizno.^2));
    plot(T,Vcplinearni,T,Vcpnelinearni,'.',T,Vcppriblizno,'--')
    grid
    xlabel T
    ylabel Vcp
    legend('Eg(T)=Eg0-a*T','Eg(t)=Eg0-(alfa*T^2)/(beta+T)','Eg(t)=Eg0')

    Is it ok? :)
     
    Last edited: Nov 17, 2013
  2. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    You tell us. What does you plot look like?
     
  3. xxxyyyba

    Thread Starter Member

    Aug 7, 2012
    249
    2
    If I knew I wouldn't ask :)
    EDIT: In expression for Vcpaprox term niaprox should be squared
     
  4. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    You don't know what your plot looks like?
     
  5. xxxyyyba

    Thread Starter Member

    Aug 7, 2012
    249
    2
    My previous post is related to wayneh's first sentence :)
    There is mistake in code?
     
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,378
    494
    There is a couple mistakes, the mistakes that I noticed were syntax mistakes, missing parenthesis, that sort of things.
     
  7. xxxyyyba

    Thread Starter Member

    Aug 7, 2012
    249
    2
    I'll be thankful if you reveal me mistakes.
     
  8. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,378
    494
    xxxyyyba likes this.
  9. xxxyyyba

    Thread Starter Member

    Aug 7, 2012
    249
    2
    Everything else is fine?
     
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