On this page, you can simulate a PN-junction using the drift-diffusion equations , a model that is often used for crystalline solar cells.
The 'single run' simulation as well as the first point of a JV curve, is always done using the timestep based method . Note that neither the size of the timestep nor the number of steps are determined automatically, you need to check yourself if convergence has been reached.
When simulating a JV curve, using the Google Chrome browser will generate the curve considerably faster. Instead of using the timestep based method, the Newton-Raphson method is available in that case .