% Code to create the required subplots for Problem Set 2, Problem 5(b)

% If you've used the same variable names as in the sample code, then you
% should be able to simply insert this into the appropriate spot in your
% own code; otherwise, you'll have to modify this accordingly, which
% should be easy to do---if disaster strikes and it doesn't work, then
% please ask for help

% The "if" statement is used to choose VD values closest to the required
% values of 0.0, 0.2, 0.3, ..., 0.8 V, and you don't need to 
% worry about how this works

if (abs(VD-0.0) <= dV/2) 
   figure(3); title('VD = 0.0 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.0 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.0 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.0 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.0 V');
elseif (abs(VD-0.2) <= dV/2) 
   figure(4); title('VD = 0.2 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.2 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.2 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.2 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.2 V');
elseif (abs(VD-0.25) <= dV/2) 
   figure(5); title('VD = 0.25 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.25 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.25 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.25 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.25 V');
elseif (abs(VD-0.3) <= dV/2) 
   figure(6); title('VD = 0.3 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.3 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.3 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.3 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.3 V');
elseif (abs(VD-0.4) <= dV/2) 
   figure(7); title('VD = 0.4 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.4 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.4 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.4 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.4 V');
elseif (abs(VD-0.5) <= dV/2) 
   figure(8); title('VD = 0.5 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.5 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.5 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.5 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.5 V');
elseif (abs(VD-0.6) <= dV/2) 
   figure(9); title('VD = 0.6 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.6 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.6 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.6 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.6 V');
elseif (abs(VD-0.65) <= dV/2) 
   figure(10); title('VD = 0.65 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.65 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.65 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.65 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.65 V');
elseif (abs(VD-0.7) <= dV/2) 
   figure(11); title('VD = 0.7 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.7 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.7 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.7 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.7 V');
elseif (abs(VD-0.8) <= dV/2) 
   figure(12); title('VD = 0.8 V');
   subplot(2,3,1); plot(f1,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.8 V');
   subplot(2,3,2); plot(D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.8 V');
   subplot(2,3,3); plot(f2,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f2(E)'); ylabel('ENERGY  [eV]'); title('VD = 0.8 V');
   subplot(2,3,5); plot(f1-f2,E,'--',D/100,E,'k-'); axis([-0.1 1.1 -1 1]);
   xlabel('f1(E)-f2(E), D(E-U)/100'); ylabel('ENERGY  [eV]'); title('VD = 0.8 V');
end