Re: PIN diode newton sec1d problem

[Carlo De Falco]

> On 2 Nov 2017, at 10:44, Carlo De Falco <address@hidden> wrote:
> 
> Hi, Indeed your initial guess is inconsistent.
> 
> You are imposing a weak p-type doping in the i region, therefore p = n = ni 
> is not correct.
> I didn't have time yet to check whether this is the reason for the simulation 
> failure.

One way to set a consistent guess would be for example

% initial guess for n, p, V, phin, phip
 V_p =  -.1;  
 V_n =  0;
 
 Fp = V_p * (D<0);
 Fn = Fp;
 
 pp = (D < 0) .* (- D + sqrt (D .^ 2 + 4 * ni ^ 2)) / 2;
 pn = (D > 0) .* ni^2 ./  ((D + sqrt (D .^ 2 + 4 * ni ^ 2)) / 2);
 p0 = (D == 0) .* ni .* ones (size (x));

 p = pp + pn + p0;

 np = (D < 0) .*  ni^2 ./  ((- D + sqrt (D .^ 2 + 4 * ni ^ 2)) / 2);
 nn = (D > 0) .* (D + sqrt (D .^ 2 + 4 * ni ^ 2)) / 2;
 n0 = (D == 0) .* ni .* ones (size (x));

 n = np + nn + n0;
 
 V = Fn + Vth * log (n / ni);

HTH,
c.