Zimnyakov Dmitry A, Vasilkov Michail Yu, Yuvchenko Sergey A, Varezhnikov Alexey S, Sommer Martin, Sysoev Victor V
Physics Department, Yuri Gagarin State Technical University of Saratov, 77 Polytechnicheskaya str., Saratov 410054, Russia.
Precision Mechanics and Control Institute of Russian Academy of Sciences, 24 Rabochayastr., Saratov 410024, Russia.
Nanomaterials (Basel). 2018 Nov 7;8(11):915. doi: 10.3390/nano8110915.
Experimental results related to the photoactivated dc conductance of anatase TiO₂ nanotubular arrays (aTNTAs) under pulsed irradiation by a laser light inside and outside the fundamental absorption band are presented. It is found that the mobility and diffusion coefficients of charge carriers in the examined aTNTA are extremely low due to a strong charge-phonon coupling, abundance of shallow traps, and hopping conductivity between adjacent nanotubes. We consider that the confining electric field appeared within the array structure due to the difference in the local concentrations of excess electrons and holes at large values of the dc conductance suppresses the drift current. In this case, the dc conductance of such aTNTAs is mainly matured by the diffusion of mobile carriers. A recurrent kinetic model for evolution of the dc conductance of aTNTAs under laser irradiation has been proposed to interpret the experimental results.
本文展示了与锐钛矿型TiO₂纳米管阵列（aTNTAs）在基波吸收带内外的激光脉冲照射下的光激活直流电导率相关的实验结果。研究发现，由于强电荷 - 声子耦合、大量浅陷阱以及相邻纳米管之间的跳跃传导，所研究的aTNTA中载流子的迁移率和扩散系数极低。我们认为，在直流电导率较大时，由于过量电子和空穴的局部浓度差异，阵列结构中出现的限制电场抑制了漂移电流。在这种情况下，此类aTNTAs的直流电导率主要由移动载流子的扩散决定。为了解释实验结果，提出了一个用于描述aTNTAs在激光照射下直流电导率演化的循环动力学模型。
