A student studied how a few parameters of the electromagnetic radiation affects the I-V(current-voltage) curve of photoelectricity. By increasing one parameter he saw that the saturation current has risen. Which parameter it was?

The saturation in the I-V curve is reached when the maximum number of photo-electrons generated by the light reach the electrode and we know that photocurrent is described by I=N*e/t, where N is the number of photo-electrons. Thus we see that to increase the photocurrent we need to increase the number of electrons. To do that we increase the intensity of the light because the more photons there are the more electrons will be released due to the photo effect.