Fabrication and resistive switching characteristics of high compact Ga-doped ZnO nanorod thin film devices

Abstract

This study investigates the resistive switching behavior of Ga-doped ZnO (GZO) nanorod thin films with various Ga/Zn molar ratios. Vertically well-aligned and uniform GZO nanorod thin films were successfully grown on Au/Ti/SiO(2)/p-Si substrates using an aqueous solution method. X-ray diffraction (XRD) results indicate that GZO nanorods have [0001] highly preferred orientation. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show the formation of highly ordered and dense nanorod thin films. These compact GZO nanorod thin films can be used to make resistive switching memory devices. Such memory devices can be reversibly switched between ON and OFF states, with a stable resistance ratio of ten times, narrow dispersion of ON and OFF voltages, and good endurance performance of over 100 cycles. The resistive switching mechanism in these devices is related to the formation and rupture of conducting filaments consisting of oxygen vacancies, occurring at interfaces between GZO nanorods (grain boundaries). Results show that the resulting compact GZO nanorod thin films have a high potential for resistive memory applications.

Compact Ga-Doped ZnO Nanorod Thin Film for Making High-Performance Transparent Resistive Switching Memory

“…4. After the GZO nanorods growth, the defects or oxygen vacancies exist on the surface of each nanorod [15], [18], [25]. In other words, most oxygen vacancies exist at the location of the grain boundaries in the GZO nanorod film.…”

“…Therefore, the ZnO-based nanorods with transparent oxide electrode would produce good transparent RS memory if we can eliminate the existing holes or gaps between each nanorod. Our previous study reported that the well-aligned and extremely dense ZnO nanorods can be grown by doping Ga ions in ZnO aqueous synthesis during fabrication [18]. Those compact nanorods are due to the Ga dopants will change the interfacial energy between the ZnO seeding layer and nanorods during the nucleation processes.…”

Enhancing the memory window of AZO/ZnO/ITO transparent resistive switching devices by modulating the oxygen vacancy concentration of the top electrode

“…Obtaining favorable endurance properties is one of the major challenges for ZnO-based T-RRAM [7][8][9][10]. It has been suggested that the memory window should achieve the requirement of at least one order of magnitude to allow for small and highly efficient sense amplifiers [11,12].…”

Bi-stable resistive switching characteristics in Ti-doped ZnO thin films

“…The doping method has already been adopted to optimize the switching performance of ZnO, including Mn, Co, Cu and Ga [15,16,18-20], but the switching properties were not as optimized as for practical applications. Very few studies of the electric conduction mechanism for Ti-doped ZnO films have been reported [21-23].…”