Matlab

clc,clear
syms x
nd=1e21*erfc(x/2/sqrt(4.85*(1e-14)*360000));
q=1.6*1e-19;
xi=1e-4;
nx=nd+1e16;
u=65+1265/(1+(nd/8.5/1e16)^0.72);
f=int(u*q*nx,x,0,xi);
rs=1/f;
rs=vpa(rs);
disp(rs);
clear;
syms x
dudu=int(1e21*erfc(x/2/sqrt(4.85*(1e-14)*3600)),x,0,1e-4);
dudu=double(dudu);
disp(dudu);
x=linspace(0,7.1*10^(-4),300);
t=1*3600.0;
temp=exp(-x.^2/4/4.85/(1e-14)/t);
y1=temp*dudu/sqrt(pi*4.85*(1e-14)*t);
plot(x,y1,':r+')
hold on
t=10*3600.0;
temp=exp(-x.^2/4/4.85/(1e-14)/t);
y1=temp*dudu/sqrt(pi*4.85*(1e-14)*t);
plot(x,y1,'-.g.')
t=100*3600.0;
temp=exp(-x.^2/4/4.85/(1e-14)/t);
y1=temp*dudu/sqrt(pi*4.85*(1e-14)*t);
plot(x,y1,'--b+')
legend("t= 1*3600 s","t=10*3600 s","t=100*3600 s")
xlabel("thickness   unit:cm")%x轴标记
ylabel("concentration C(c,t)  unit:cm\^(-3)")%y轴标记
title("concentration")%标题

最后效果图：