Localization crossover and phase coherent electron transport in a-lnGaZnO_4 thin films

摘要

Electrical and magnetotransport properties have been studied on pulsed laser deposition grown amorphous InGaZnO_4 thin films exhibiting different disorder. A crossover from strong to weak localization was observed as disorder (quantified by a parameter k_fl) decreases. The sample with k_fl value 0.04 showed strong localization behavior whereas for the sample with k_fl> 1, electron transport is governed by weak localization. The samples with k_fl > 1 showed negative magnetoresistance (MR) because of the suppression of weak localization. From the MR study, we estimated the phase coherence length which scales with temperature as T~(-3/4).The maximum phase coherence length was found to be 130nm at 5K for the sample with k_fl— 1.71 and this can significantly influence the spintronic research in amorphous semiconductors.