Solution-Processable Growth and Characterization of Dandelion-like ZnO:B Microflower Structures

• Published in: Crystals (Basel) Vol. 12; no. 1; p. 11
• Main Authors: Erat, Selma, Braun, Artur, Çetinkaya, Samed, Yildirimcan, Saadet, Kasapoğlu, Ahmet Emre, Gür, Emre, Harputlu, Ersan, Ocakoglu, Kasım
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2022
• Subjects: Activation energy; Aqueous solutions; Boron; Crystallites; dandelion; Doping; Electron micrographs; Energy; Energy gap; High temperature; Low temperature; Mathematical analysis; Methods; micro rods; Molecular beam epitaxy; Nanoparticles; Nanorods; Nitrates; Photoelectric emission; Photovoltaic cells; Radio frequency; Raman spectra; Semiconductors; Solar cells; Thin films; Zinc oxide; Zinc oxides; ZnO
• ISSN: 2073-4352; 2073-4352
• DOI: 10.3390/cryst12010011

Intrinsic and dandelion-like microflower nano-rod structures of boron-doped ZnO thin films were synthesized with an ecofriendly and cost-effective chemical bath deposition technique from an aqueous solution of zinc nitrate hexahdyrate [Zn(NO3)2.6H2O] as a precursor solution and boric acid as a doping solution. The boron concentrations were 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, and 7.0 by volume. Scanning electron micrographs showed that doping with boron appears to hinder the vertical alignment of crystallites. Additionally, independent hexagonal nano-rod structures were observed to coalesce together to form dandelion-like structures on the film’s surface. The atomic ratio of the elements was determined via the X-ray photoemission spectrum technique. There were no substantial changes in the vibration structure of the film upon doping in terms of the Raman spectra. The optical band gap of ZnO (3.28 eV) decreased with B doping. The band gap of the ZnO:B film varied between 3.18 and 3.22 eV. The activation energy of the ZnO was calculated as 0.051 eV, whereas that of the ZnO:B film containing 1.0% B was calculated as 0.013 eV at low temperatures (273–348 K), versus 0.072 eV and 0.183 eV at high temperatures (348–523 K), respectively. Consequently, it can be interpreted that the 1% B-doped ZnO, which has the lowest activation energy at both low and high temperatures, may find some application areas such as in sensors for gases and in solar cells.