How to determine the reverse saturation current

I am trying to find out the reverse saturation current in here, but somehow the code isn't running. Can anyone help?

 N_a=1.0*10^22;
 N_d=1.0*10^22;
 ni=1.5*10^16;
 D_n=0.0025;
 tao_p0=5*10^(-7);
 tao_n0=5*10^(-7);
 D_p=0.001;
 E_r=11.7;
 Js=(ni)^2*(1/N_a(D_n/tao_n0)^1/2+1/N_d(D_p/tao_p0)^1/2);

Index exceeds the number of array elements. Index must not exceed 1.

Answer 1

[Star Strider]

I believe at least two multiplication operators are missing, after the ‘Na’ and‘Nd’ references:

 N_a=1.0*10^22;
 N_d=1.0*10^22;
 ni=1.5*10^16;
 D_n=0.0025;
 tao_p0=5*10^(-7);
 tao_n0=5*10^(-7);
 D_p=0.001;
 E_r=11.7;
 Js=(ni)^2*(1/N_a*(D_n/tao_n0)^1/2+1/N_d*(D_p/tao_p0)^1/2)

Js = 7.8750e+13

I do not see that any elements are vectors, however it might be best to vectorise the ‘Js’ assignment in the event that could be in a future version of the code.

.

Answer 2

[David Hill]

missing * and some () in last equation

N_a=1.0*10^22;
N_d=1.0*10^22;
ni=1.5*10^16;
D_n=0.0025;
tao_p0=5*10^(-7);
tao_n0=5*10^(-7);
D_p=0.001;
E_r=11.7;
Js=(ni)^2*(1/(N_a*(D_n/tao_n0)^1/2)+1/(N_d*(D_p/tao_p0)^1/2));