2018/02/13 by Juanxiu Xiao, Tun Seng Herng, Xiao, Juanxiu +5
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.1802.04494
29 oages, 6 Figures
arxiv created 2018/02/13 · arxiv updated 2018/02/14
This paper presents multiple-modes Scanning Probe Microscopy (SPM) studies on characterize resistance switching (RS), polarization rotation (PO) and surface potential changes in copper doped ZnO (ZnO:Cu) thin films. The bipolar RS behavior is confirmed by conductive Atomic Force Microscopy (c-AFM). The PO with almost 180° phase angle is confirmed by using the vertical and lateral Piezoresponse Force Microscopy (PFM). In addition, it elucidates that obvious polarization rotation behavior can be observed in the sample with increasing Cu concentration. Furthermore, correlation of the RS behavior with PO behavior has been studied by performing various mode SPM measurements on the same location. The electric field resulted from the opposite polarization orientation are corresponded to the different resistance states. It is found that the region with the polarization in downward direction has low resistance state (LRS), whereas the region with upward polarization has high resistance state (HRS). In addition, the Piezoresponse Force Spectroscopy (PFS) and Switching Spectroscopy PFM (SS-PFM) measurements further confirm that the existence of the built-in field due to the uncomplemented polarization may affect the depletion region and hence contribute to the RS behavior. In addition, Kelvin Probe Force Microscopy (KPFM) results show that, when ZnO-based thin films is subjected to negative and then followed by positive sample bias, injection charge limit current is dominated.