Optical and resistive switching properties of Chitosan-aluminum-doped zinc oxide composite thin films for transparent resistive random access memory application

Abstract

The preparation of chitosan-aluminum-doped zinc oxide (AZO) composite thin films for transparent resistive random access memory applications is reported. The variation in optical transmission, refractive index and optical bandgap of the composite films as a function of concentration of Al in ZnO and AZO weight percent in chitosan is investigated. Independent of composition, optical transmission is of the order of 87–89% at 550 nm. The refractive index at this wavelength is in the range of 1.71–1.86. The composite films exhibit reversible resistive switching behavior which is dependent on the Al concentration in ZnO as well as the weight percent of AZO in chitosan. There is a threshold Al concentration in ZnO, below and above which resistive switching is not observed. At the threshold concentration, resistive switching behavior is stable over several cycles. The co-existence of unipolar and bipolar switching controlled by Al concentration in ZnO is also observed. The current study establishes the potential of chitosan-AZO composite thin films for transparent resistive random access memory application.