Investigation of hydrothermal growth time and temperature for optimized ZnO nanowire arrays toward photovoltaics

• Published in: Surfaces and interfaces 2023-08, Vol.40, p.103123, Article 103123
• Main Authors: Dloo, A., Fazouan, N., Atmani, E.H.
• Format: Article
• Language: English
• Subjects: Growth temperature; Growth time; Hydrothermal method; Photovoltaic; Structural and optical correlation; ZnO nanowires
• ISSN: 2468-0230; 2468-0230
• DOI: 10.1016/j.surfin.2023.103123

The challenge of meeting energy demands has led to the development of nanotechnology. Semiconductor nanowires are considered a promising option among various nanomaterials for efficiently capturing solar radiation in an axial geometry. This work presents the growth of ZnO nanowire arrays on seeded-coated glass substrates using a two-step hydrothermal method, by examining the effect of two crucial hydrothermal growth parameters: time and temperature of growth. X-ray diffraction (XRD) spectra showed the hexagonal wurtzite shape of the ZnO nanowires which displayed a preferred (002) axial orientation. To estimate the crystallite size, strain, stress, and energy density values, we used the Modified Williamson-Hall models. Scanning electron microscopy (SEM) observations showed that the growth time and temperature have a significant impact on the length and diameter of the nanowires, which increase with increasing time and temperature. A clear correlation was also observed between the diameter and density of the nanowires. Optical analysis showed that ZnO nanowires exhibited good transmittance of about 90% in the near ultraviolet and visible spectrum, but this decreased with increasing growth time and temperature. The measured bandgap energy showed a red shift, which confirmed its correlation with the structural characteristics. The improved optical and structural features of ZnO nanowires were analyzed with regards to their potential use in photovoltaics. [Display omitted]