Growth kinetics of crumb-like structure formation on SnO2 nanowires during direct oxidation

Vivekanandan Alangadu Kothandan; Chang Shao-Fu; Li Zhong-You; Chen Shih-Hsun

doi:10.1016/j.heliyon.2023.e20519

Growth kinetics of crumb-like structure formation on SnO₂ nanowires during direct oxidation

Heliyon. 2023 Sep 28;9(10):e20519. doi: 10.1016/j.heliyon.2023.e20519. eCollection 2023 Oct.

Authors

Vivekanandan Alangadu Kothandan^{1

2}, Chang Shao-Fu², Li Zhong-You², Chen Shih-Hsun²

Affiliations

¹ Department of Aeronautical Engineering, Annasaheb Dange College of Engineering and Technology, Ashta, Sangli, 416301, Maharashtra, India.
² Department of Mechanical Engineering, National Yang Ming Chiao Tung University, Hsinchu 300039, Taiwan.

Abstract

A facile AAO (anodic aluminum oxide) template-assisted vacuum die-casting technique was used to create Sn nanowires and convert them into SnO₂ without degrading the wires nanostructure. As a function of time and temperature, the controlled oxidation on the Sn nanowires of two different spatial configurations (100 and 250 nm in diameter) revealed distinct oxidation mechanisms. The 250-SnO₂ nanowires exhibits a peculiar crumb-like structure formation over the surface due to the higher level of Sn atom dislocation. Conversely, the sub-100 nm SnO₂ nanowires shows a highly crystalline, homogenous, and defect-free surfaces. The optical properties of the sub-100 nm SnO₂ nanowires were characterized using UV-Vis spectroscopy. The heat-treated tin oxides nanowires samples at temperatures of 300, 500, and 700 °C for 7 h exhibited optical energy bandgaps of 1.8, 2.6, and 3.3 eV, respectively. The observed variation in bandgap is attributed to the unique phase compositions achieved in each of the heat-treated samples. Moreover, the obtained results showed exceptional structural integrity and optical properties that are inherently interconnected with the diverse phases achieved under precise heat treatment conditions.

Keywords: Anodic aluminum oxide; Bandgap; Metal oxide; Nanowire; Vacuum die-casting.