Nanopowder and Thin Films of ZnO by Sol Gel Approach

Authors Ankita, Sanjay Kumar , Sudhir Saralch , Dinesh Pathak

Department of Physics, Sri Sai University, Palampur, India

Issue Volume 11, Year 2019, Number 4
Dates Received 22 November 2018; revised manuscript received 0 August 2019; published online 22 August 2019
Citation Ankita, Sanjay Kumar, Sudhir Saralch, Dinesh Pathak, J. Nano- Electron. Phys. 11 No 4, 04027 (2019)
PACS Number(s) 68.55. − a, 68.37.Hk
Keywords TCO (2) , Dip coating (4) , Structural properties (9) , Band gap (29) .

In this work we have studied the structural and optical properties of ZnO thin films. Pure thin films of ZnO were prepared on glass substrate by sol gel dip coating method and annealed at a temperature of 150 ºC. Similarly, 1 gm PVA capped ZnO thin film was prepared and annealed at 250 ºC and the last sample of 2 gm PVA capped ZnO thin film was prepared and annealed at a temperature of 350 ºC. The increase in sol aging time resulted in a gradual improvement in crystallinity of the hexagonal phase for all diffraction peaks. Effect of sol aging on optical transparency is quite obvious through increased transmission with prolonged sol aging time. Interestingly, 24 hour sol aging time was found to be optimal to achieve smooth surface morphology, good crystallinity and high optical transmittance which were attributed to an ideal stability of solution. The ZnO thin films have been characterized in terms of morphological, structural and optical properties by scanning electron microscopy (SEM) and ultraviolet–visible (UV–Vis) spectroscopy. The UV–Vis transmittance spectrum of synthesized sample gives the optical band gap value of 3.2 eV, 3.15 eV and 3.1 eV. Along with thin films, nanopowder is also synthesized by sol gel method and characterized by XRD, which can be potentially used in cosmetic industry. Sol-gel dip coating technique creates pure and capped ZnO films with potential for applications as transparent conducting electrodes in optoelectronic devices such as solar cell and light emitting diodes.

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