Journal of Surface Science and Technology

C. Rameshkumar ¹, R. Subalakshmi ²

Affiliations
1 Department of Physics, Sathyabama University, Chennai – 600 119, Tamil Nadu, IN
2 Department of Physics, University of Madras, Chennai - 600 005, Tamil Nadu, IN

Abstract

Undoped and Aluminum-doped ZnO thin films are prepared by ultrasonic spray pyrolysis at 400 °C on glass substrates were investigated. The dopant solution is taken at the atomic percentage of 1 to 5. By using X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM), the crystallographic properties and surface morphology of the films were characterized. The X-ray diffraction results show that the pure ZnO thin films have polycrystalline nature and possess a typical hexagonal wurtzite structure. Compared to pure ZnO thin film, the grain size in the Al-doped thin film is increased. They are well crystallized and the grain size is (e = 0.13 μm) for Al-doped ZnO and (e = 0.1 μm) for undoped ZnO. Compared to the previous reports, grain size of the ZnO thin film also increases with the increasing annealing temperature.

Keywords

Optoelectronic Devices, Spray Pyrolysis, Thin Film.

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C. Rameshkumar ¹, S. Sarojini ², K. Naresh ¹, R. Subalakshmi ³

Affiliations
1 Department of Physics, Sathyabama University, Chennai - 600119, Tamil Nadu, IN
2 Department of Physics, Queen Mary’s College, Chennai - 600004, Tamil Nadu, IN
3 Departments of Physics, Madras University, Chennai - 600009, Tamil Nadu, IN

Abstract

The PMMA and PVDF thin films were synthesized by solution casting process. The structural, spectroscopic, and morphological attributes of both the interface and surface of the film have been investigated. The structural properties of pristine PMMA and PVDF thin film were studied by XRD. The XRD spectra showed the detailed state of order and disorder of the system. From the XRD studies amorphous nature as well as the crystallanity (semi crystalline nature) of the polymer thin film were identified. SEM showed the surface morphology of the pristine PMMA and PVDF thin film. From the SEM image the size and the porous nature of the thin film were estimated. The UV showed the absorption characteristics of PMMA and PVDF thin films. From the UV-Visible spectra, we determined the direct and indirect optical energy gap of pristine PMMA and PVDF polymer samples by Devi's and Mott formula and Tauc's Expression. To the best of our knowledge, the direct and indirect energy gap in pristine PMMA and PVDF polymer thin films have been observed for the first time as no such report was found in literature survey.

Keywords

Polycrystalline Surfaces, Polycrystalline Thin Films, XRD, Visible/Ultraviolet Absorption Spectroscopy, Scanning Electron Microscopy (SEM), Optical Band Gap.

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