Influences of Cu Doping on the Microstructure, Optical and Resistance Switching Properties of Zinc OxideThin Films

Jun-Hong Weng; Ming-Cheng Kao; Kai-Huang Chen; Men-Zhe Li

doi:10.3390/nano13192685

Influences of Cu Doping on the Microstructure, Optical and Resistance Switching Properties of Zinc OxideThin Films

Nanomaterials (Basel). 2023 Sep 30;13(19):2685. doi: 10.3390/nano13192685.

Authors

Jun-Hong Weng¹, Ming-Cheng Kao², Kai-Huang Chen³, Men-Zhe Li⁴

Affiliations

¹ Department of Electrical Engineering, Tunghai University, Taichung 40704, Taiwan.
² Department of Information and Communication Engineering, Chaoyang University of Technology, Taichung 413310, Taiwan.
³ Department of Electronic Engineering, Center for Environmental Toxin and Emerging-Contaminant Research, Super Micro Mass Research & Technology Center, Cheng Shiu University, Chengcing Rd., Niaosong District, Kaohsiung 83347, Taiwan.
⁴ Department of Electronic Engineering, Hsiuping University of Science and Technology, Taichung 41280, Taiwan.

Abstract

Copper-doped zinc oxide films (Zn_1-xCu_xO) (x = 0, 2%, 4%, 6%) were fabricated on conductive substrates using the sol-gel process. The crystal structure, optical and resistive switching properties of Zn_1-xCu_xO films are studied and discussed. RRAM is made using Zn_1-xCu_xO as the resistive layer. The results show that the (002) peak intensity and grain size of Zn_1-xCu_xOfilms increase from 0 to 6%. In addition, PL spectroscopy shows that the oxygen vacancy defect density of Zn_1-xCu_xO films also increases with the increase in Cu. The improved resistive switching performance of the RRAM device can be attributed to the formation of conductive filaments and the destruction of more oxygen vacancies in the Zn_1-xCu_xO film. Consequently, the RRAM device exhibits a higher low resistance state to high resistance state ratio and an HRS state of higher resistance value.

Keywords: ZnO; resistive switching; sol-gel; thin films.

Grants and funding

This work was supported by the National Science Council of the Republic of China under Contract No. NSC MOST 111-2637-E-164-002.