I(V)-curves

In the figure typical I(V)-curves at different illumination intensities are plotted. The current plateau due to the pinch off in the n-layer shifts upwards if the illumination is increased. The I(V)- curves in the upper half are received using contacts directly after fast In diffusion resulting in a relatively high leakage due to break-through. This leakage can be lowered drastically by annealing providing smooth junctions from the contacts to the p-layers (lower half). With increasing intensity also the slope at the origin which corresponds to the small signal photoconductivity is increasing.