Size reduction process by novel TVA technique and its effect on enhancement of physical properties of oxide semiconductor pellets

ABSTRACT

This work describes a novel approach that can reduce grain as well as particle size of semiconducting pellet samples in the nanoscale range with low-cost and less instrumentation. Herein an instrumental setup was designed and fabricated in-house, referred to as the ‘Thermo-Vibrational Annealing’ (TVA) setup. Here, the concept of grain confinement within the pellet during the recrystallisation phase of annealing was achieved by simultaneously applying both thermal and vibrational mechanical energy to the sample, followed by vibrational dry quenching. In this work, for the case study, ZnO pellets were prepared by using chemical route pyrophoric method followed by annealing at 800°C for 4 hours using this setup. The reduction of particle and grain size by this TVA, in comparison to without vibrational annealing, was confirmed by X-ray diffraction (XRD), high-resolution transmission electron microscopy and scanning electron microscopy studies. The expected changes in other microstructural and optical properties were examined by Raman and UV-Visible absorption spectroscopy studies. Moreover, this work gives references to improve the physical properties not only of ZnO but also of other oxide semiconductor samples using this technique, to be used in multiple sensors and optoelectronic devices.

KEYWORDS:

• Nano-scale technology
• size reduction
• nano-ZnO
• vibrational temperature
• dry cooling system
• grain morphology

Acknowledgements

We are grateful to National Institute of Science Education and Research (NISER), Bhubaneswar for supporting our work and for HRTEM measurements. We are thankful to University of North Odisha for providing facility for UV-Visible spectroscopy and CIF, O.U.A.T., Bhubaneswar for SEM and EDX spectra measurements. We would also like to thanks the Department of Atomic energy, UGC-DAE-CSR, INDORE for Raman spectroscopy measurements.

Disclosure statement

No potential conflict of interest was reported by the authors.