Fractality and roughness of the ZnO:Cu composite thin films annealed in different temperatures

ABSTRACT

In this study, we co-sputtered zinc dioxide and copper in order to manufacture a composite thin film. We then used atomic force microscopy (AFM), scanning electron microscopy and energy-dispersive X-ray spectroscopy to investigate the surface morphology of samples. We annealed four samples to temperatures ${100}^{\circ }\mathrm{C},{200}^{\circ }\mathrm{C},{400}^{\circ }\mathrm{C}$ and ${800}^{\circ }\mathrm{C}$ for 90 minutes. Afterwards, we employed height distribution, roughness, permutation entropy(PE) and fractality of the height data from AFM to analyse samples theoretically. Our results reveal that although the roughness will increase by temperature and the multifractal spectrum widens by it; the PE does not change both from ${100}^{\circ }\mathrm{C}$ to ${200}^{\circ }\mathrm{C}$ and from ${400}^{\circ }\mathrm{C}$ to ${800}^{\circ }\mathrm{C}$. Both PE and height distribution are changing meaningfully only in increasing the temperature from ${200}^{\circ }\mathrm{C}$ to ${400}^{\circ }\mathrm{C}$.

KEYWORDS:

• Roughness
• permutation entropy
• atomic force microscopy (AFM)
• multifractal analysis
• composite thin film
• temperature

Acknowledgement

The authors would like to acknowledge the support from Nanostructured Coating Co., especially Mr Mahdavi for equipping of sputtering system, Mrs Keshtmand for contributions to the preparation of samples, Mrs Fesahat and Mr Kardan for AFM imaging.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

RouhollahHaji Abdolvahab http://orcid.org/0000-0003-3498-4864

AliKosari Mehr http://orcid.org/0000-0002-1807-3625