Basically, the program computes the current density as a function of
bias. Then the bias and current are calculated with assuption of the
uniform current spreading, taking into account user-defined series
resistance and specific resistance at contacts between the
semiconductor and metal electrodes (see Eq. 7.1 of Sec 7 of SiLENSe
Physics Summary). The total LED is considered as series connection of
an p-n junction and a series resistance.
The p-n junction current exponentially raises with the p-n junction
voltage drop. So the p-n junction limit the current at low voltages.
At high voltages, the current is limited by the resistance and the I-V
curve is nearly linear.
