Laser Flash Induced Charge Carrier Transfer in Polycrystalline n‐TiO₂ Semiconductors

Abstract

Photocurrent and photovoltage transients have been measured at n‐TiO2 electrolyte junctions by means of ns‐laser pulse excitation. Two different kinds of build‐up, independent of excitation intensity and external resistance have been observed. It is concluded that the charge carrier transit through the depletion layer is the rate determining step if traps or grain boundaries of the microcrystals acting as such, play a significant role. The result is a longer rise time of either photocurrent or ‐voltage, which exceeds the laser pulse width by orders of magnitude.