Synthesis and Characterization of Copper Doped Zinc Oxide Thin Films Deposited by RF/DC Sputtering Technique

doi:10.1007/s12204-022-2462-1

Abstract

Abstract: Undoped and copper (Cu) doped zinc oxide (Zn1-xCuxO, where x = 0—0.065) nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering technique. The aim of this work is to investigate the crystal structure of ZnO and Cu doped ZnO thin films and also study the effect of Cu doping on optical band gap of ZnO thin films. The identification and confirmation of the crystallinity, film thickness and surface morphology of the nano range thin films are confirmed by using X-ray diffractometer (XRD), scanning electron microscope and atomic force microscope. The XRD peak at a diffractive angle of 34.44° and Miller indices at (002) confirms the ZnO thin films. Crystallite size of undoped ZnO thin films is 27 nm and decreases from 27 nm to 22 nm with increasing the atomic fraction of Cu (x_Cu) in the ZnO thin films from 0 to 6.5% respectively, which is calculated from XRD (002) peaks. The different bonding information of all deposited films was investigated by Fourier transform infrared spectrometer in the range of wave number between 400 cm^-1 to 4 000 cm^-1. Optical band gap energy of all deposited thin films was analyzed by ultraviolet visible spectrophotometer, which varies from 3.35 eV to 3.19 eV with the increase of x_Cu from 0 to 6.5% respectively. Urbach energy of the deposited thin films increases from 115 meV to 228 meV with the increase of x_Cu from 0 to 6.5% respectively.

Key words: Cu-ZnO thin films, RF/DC sputtering technique, X-ray diffraction, atomic force microscope, optical property, Urbach energy

摘要： 采用射频/直流反应溅射技术在玻璃衬底上制备了未掺杂和掺铜氧化锌（Zn_1-xCu_xO，其中x = 0~0.065）的纳米晶体薄膜。本工作旨在研究ZnO和Cu掺杂ZnO薄膜的晶体结构，并研究Cu掺杂对ZnO薄膜光学带隙的影响。利用X射线衍射仪（XRD）、扫描电子显微镜和原子力显微镜对纳米级薄膜的结晶度、薄膜厚度和表面形貌进行了鉴定和确认。在衍射角34.44°密勒指数（002）的XRD峰值证实了ZnO薄膜的存在。由XRD（002）峰计算得出，当ZnO薄膜中Cu的原子分数（x_Cu）从0增加到6.5%时，未掺杂ZnO薄膜的晶粒尺寸从27 nm减小到22 nm。通过傅里叶变换红外光谱仪研究了在400~4000 cm^-1波数范围内所有沉积薄膜的不同键合信息。通过紫外可见分光光度计分析了所有沉积薄膜的光学带隙能：随着xCu从0增加到6.5%，其变化范围为3.35 eV到3.19 eV。随着x_Cu从0增加到6.5%，沉积薄膜的Urbach能量从115 meV增加到228 meV。

关键词: Cu-ZnO薄膜；射频/直流溅射技术；X射线衍射；原子力显微镜；光学性质；Urbach能量

CLC Number:

O 484

KHAN Mohibul, ALAM Md. Shabaz, AHMED Sk. Faruque∗. Synthesis and Characterization of Copper Doped Zinc Oxide Thin Films Deposited by RF/DC Sputtering Technique[J]. J Shanghai Jiaotong Univ Sci, 2023, 28(2): 172-179.

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