%Variation of Ideal-Diode I-V  with semiconductor doping.

%Si step junction, T = 300K.

%In response to the "ND=" prompt type [ND1 ND2 ...] to input

%multiple doping values.



%Initialization and Universal Constants

clear

k=8.617e-5;

q=1.6e-19;



%Device, Material, and System Parameters

A=1.0e-4;

ni=1.0e10;

taup=1.0e-6;

ND=input('Input the n-side doping concentration, ND = ');

T=300;



%Hole Mobility Calculation

NAref=2.35e17;

upmin=54.3;

up0=406.9;

ap=0.88;

up=upmin+up0./(1+(ND./NAref).^ap);

%The mobility calculation here assumes the hole minority carrier

  %mobility is equal to the hole majority carrier mobility.



%I-V Calculation

VA=linspace(-1,0.2);

DP=k.*T.*up;

LP=sqrt(DP.*taup);

I0=q.*A.*(DP./LP).*(ni^2 ./ND)

I=I0.'*(exp(VA./(k.*T))-1);



%Plotting Result

close

plot(VA,I); grid;

ymin=-2*I0(1);  ymax=5*I0(1);

axis([-1,0.2,ymin,ymax]);

xlabel('VA (volts)');  ylabel('I (amps)');



%Adding axes,key

xx=[-1 0.2];  yx=[0 0];

xy=[0 0]; yy=[ymin,ymax];

hold on

plot(xx,yx,'-w',xy,yy,'-w');

j=length(ND);

for i=1:j;

    yput=(0.70-0.06*i)*ymax;

    yk(i,1)=yput; yk(i,2)=yput;

    text(-0.68,(0.69-0.06*i)*ymax,['ND=',num2str(ND(i)),'/cm3']);

end

xk=[-0.8 -0.7];

plot(xk,yk);

text(-0.74,0.75*ymax,'Si, 300K');

hold off