Contents lists available at ScienceDirect Materials Science in Semiconductor Processing journal homepage: www.elsevier.com/locate/mssp Transparent hybrid ZnO-graphene film for high stability switching behavior of memristor device T.N.T.A. Aziz, A.B. Rosli, M.M. Yusoff, S.H. Herman, Z. Zulkifli ⁎ Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia ARTICLE INFO Keywords: ZnO Graphene TCVD Water bath Memristor device ABSTRACT The objective of this study was to obtain high stability of switching behavior by employing hybrid Zinc Oxide- Graphene (ZnO-G) structure in memristor device. ZnO was grown on a glass substrate using thermal chemical vapor deposition (TCVD) at different substrate temperature of 350 °C, 450 °C and 550 °C. Graphene in water solution was transformed on ZnO thin film using water bath at 90 °C. Raman spectra and FESEM images showed that the thin film exhibited multilayers graphene on ZnO surface has been formed. The multilayer graphene is highly transparent as the ZnO surface morphology can be observed underneath the graphene layer. Switching cycle was found consistent even after several cycles. Due to the limited oxygen ion mobility present in the oxide bulk, the switching cycle of hybrid ZnO-G devices can be repeated many times without degrade which showed more stable properties than those of ZnO devices. From I-V characteristic, it was found that high serial resistance of graphene is contributed to the reduced current consumption of Graphene-based devices to 200 μA. The finding showed that, hybrid ZnO-G structure has been successfully fabricated on glass substrate with stable switching properties compared to pristine ZnO memristive device. 1. Introduction The focus by a semiconductor industry has turned in recent years to develop nanoscale structures that are aligned with device miniatur- ization and performance. The efforts need to match the demands of new era of computing and electronic devices. Transparent electronic devices have become increasingly attracted by researcher to create a see- through embedded electronic system. In some application of electronic devices, the transparent and conductive materials can be manufactured in a low cost and large area since the electrode and the substrate are from the same material [1]. In an application of non-volatile memory devices, an excellent of optical transparency is essential for charge trapping capability [2]. In this regard, memristors development is fitting with this frame- work because memristive devices are highly scalable to the tune of nanometer scale [3]. Such devices have great potentials in applications such as non-volatile memory and resistive switching devices. Many studies have been performed on various materials that are suitable for this purpose. Among them are perovskite oxide materials [4], binary transition metal oxides (like ZnO [5], TiO 2 [6], Ta 2 O 5 [7], NiO [8]), chalcogenides [9], organic materials [10,11] and carbon-based devices, specifically those based on Graphene and Graphene Oxide [12]. Among the potential materials for memristor devices, ZnO were the most material chosen by researcher due to the properties of ZnO. The memristive behavior of ZnO film can be triggered by some external sources such as visible-light-activated that can be absorbed by ZnO film to show the switching properties [13]. Besides that, the performance of ZnO memristor device are also depend on the material used for the electrode. Pt was found to have a large work function and forming Schottky contact with ZnO film that affect the hysteresis loop of memristive behavior [14]. However, fabrication of memristor devices from pristine material may show irregularities in terms of switching cycles and need improvement in charge retention characteristics. Metal oxides such as ZnO can be prepared in various techniques such as nanocomposite [15] and hybrid structure (layer by layer). Numerous studies on hybrid structured thin film have showed excellent stability in electrical, optical, mechanical and cycling properties [16,17]. The hybrid structures of ZnO-G based devices were used in various applications such as thin film transistors (TFTs) [18,19], field emission display [20], sensors [21] and memory devices [22]. There is a report on the integration of large-area CVD Graphene into titanate- based memristive devices has reduced switching power and nonlinear I- V characteristics while maintaining the device performance [23]. The hybrid devices can be fabricated by several combination methods such as thermal chemical vapor deposition (TCVD), atomic layer deposition (ALD), radio frequency (RF) sputtering, modified Hummer methods and https://doi.org/10.1016/j.mssp.2018.08.029 Received 12 April 2018; Received in revised form 31 July 2018; Accepted 25 August 2018 ⁎ Corresponding author. E-mail address: zurita101@salam.uitm.edu.my (Z. Zulkifli). Materials Science in Semiconductor Processing 89 (2019) 68–76 1369-8001/ © 2018 Elsevier Ltd. All rights reserved. T