Summary

	Surface Condition	U (for n-type material)	J0
Wide-base diode	Far away	$U={\displaystyle \frac{\mathrm{\Delta }p}{{\tau }_p}}$	$J_0=q({\displaystyle \frac{D_n{n}_i^2}{L_n{N}_A}}+{\displaystyle \frac{D_p{n}_i^2}{L_p{N}_D}})$
Narrow Base diode	Infinite Dp = 0	U = 0	$J_0=q({\displaystyle \frac{D_n{n}_i^2}{W_{emitter}{N}_A}}+{\displaystyle \frac{D_p{n}_i^2}{W_{base}{N}_D}})$
General case	Infinite Dp = 0	$U={\displaystyle \frac{\mathrm{\Delta }p}{{\tau }_p}}$	$J_0=q[{\displaystyle \frac{D_n{n}_i^2}{L_n{N}_A}}\coth \left({\displaystyle \frac{W_P}{L_n}}\right)+{\displaystyle \frac{D_p{n}_i^2}{L_p{N}_D}}\coth \left({\displaystyle \frac{W_N}{L_p}}\right)]$
	$I=I_0(e^{\frac{qV}{kT}}-1)-I_{SC}$	$U={\displaystyle \frac{\mathrm{\Delta }p}{{\tau }_p}}$	$J_0=q[{\displaystyle \frac{D_n{n}_i^2}{L_n{N}_A}}\times {\displaystyle \frac{\cosh \left({\displaystyle \frac{W_P}{L_n}}\right)+{\displaystyle \frac{D_n}{S_n{L}_n}}\sinh \left({\displaystyle \frac{W_P}{L_n}}\right)}{{\displaystyle \frac{D_n}{S_n{L}_n}}\cosh \left({\displaystyle \frac{W_P}{L_n}}\right)+\sinh \left({\displaystyle \frac{W_P}{L_n}}\right)}}+{\displaystyle \frac{D_p{n}_i^2}{L_p{N}_D}}\times {\displaystyle \frac{\cosh \left({\displaystyle \frac{W_N}{L_p}}\right)+{\displaystyle \frac{D_p}{S_p{L}_p}}\sinh \left({\displaystyle \frac{W_N}{L_p}}\right)}{{\displaystyle \frac{D_p}{S_p{L}_p}}\cosh \left({\displaystyle \frac{W_N}{L_p}}\right)+\sinh \left({\displaystyle \frac{W_N}{L_p}}\right)}}]$