The I-V graph gives information on the resistance of the device.
A graph that tends to a greater slope signals a decrease in resistance and a graph tending towards the horizontal indicates a increase in resistance. In short , the ease at which current increase with voltage indicates the resistance of the device. Th find the lowest resistance one need draw the steepest slope starting from origin and see where the line intersect with the curve in the graph. The gradient is not the resistance . The resistance is the p.d divide by current(y/x) at the location of the graph.
