When an electrode made of semiconductor nanotubes/nanowires etc is illuminated an overshoot or transient maximum in the photocurrent is observed. The photocurrent gradually exponentially decreases from the transient maximum and gets saturated after some time.
However, there are also some cases, where the photocurrent keeps increasing instead of decreasing. Why does this increment happen? What is the proper reason behind this? Please explain with proper references.
Thanks in advance.