Effect of Annealing Time on the Optical and Structural Properties of ZnO Nanorods

Authors A.K. Bhunia1, S.S. Pradhan2, S. Saha3

1Department of Physics, Government General Degree College at Gopiballavpur-II, Beliaberah, Jhargram, West Bengal 721517, India

2Department of Physics, Midnapore College (Autonomous), Paschim Medinipur, West Bengal 721102, India

3Department of Physics & Technophysics, Vidyasagar University, Paschim Medinipur, West Bengal 721102, India

Е-mail amitphysics87@gmail.com
Issue Volume 11, Year 2019, Number 6
Dates Received 13 August 2019; revised manuscript received 05 December 2019; published online 13 December 2019
Citation A.K. Bhunia, S.S. Pradhan, et al., J. Nano- Electron. Phys. 11 No 6, 06003 (2019)
DOI https://doi.org/10.21272/jnep.11(6).06003
PACS Number(s) 78.66.Bz, 81.40.Vw
Keywords ZnO nanocrystals, Band gap (29) , Emission spectrum, XRD (80) , TEM (74) .

Zinc oxide nanorods (NRs) are successfully synthesized by simple chemical precipitation method using zinc nitrate hexahydrate and sodium hydroxide as the precursors. The effect of annealing at 400 °C for 2 h and 4 h on the ZnO sample is investigated by UV-Vis spectroscopy, emission spectrum and XRD analysis. The band gap of NRs decreased from 3.86 eV to 3.54 eV and Urbach energy increased from 1.33 eV to 1.75 eV under heat treatment. Strong excitonic related UV emission at 381 nm, 399 nm, 394 nm and defect related emissions in the visible regions are observed from ZnO NRs. X-ray diffraction study revealed that the ZnO NRs are highly crystalline and have a pure hexagonal phase. The results revealed that grain size increases and strain decreases after annealing the ZnO NRs. Well crystalline ZnO NRs with aspect ratio of about 4.25 and bright diffraction spots are observed from TEM and SAED patterns.

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