Role of defects and microstructure on the electrical properties of solution-processed Al-doped ZnO transparent conducting films

• Published in: Applied physics. A, Materials science & processing Vol. 126; no. 8
• Main Authors: Kumar, Anurag, Ahmad, Imteyaz
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2020; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Crystal defects; Crystallites; Diffraction patterns; Electrical properties; Electrical resistivity; Glass substrates; Hall effect; Machines; Manufacturing; Materials science; Microstructure; Nanotechnology; Optical and Electronic Materials; Optical properties; Pattern analysis; Photoelectrons; Photoluminescence; Photovoltaic cells; Physics; Physics and Astronomy; Processes; Sol-gel processes; Solar cells; Spectrum analysis; Spin coating; Surfaces and Interfaces; Thin Films; Wurtzite; X ray photoelectron spectroscopy; Zinc oxide; Thin films; UV–Vis; Transparent conducting oxides; Spin coating; Photoluminescence; Aluminium-doped zinc oxide (AZO); XPS
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-020-03767-0

A cheaper, non-vacuum-based routes are required for the large-scale implementation of TCOs in solar cells and LEDs. Generally, solution-based processing routes result in lower transparency and greater resistivity. To achieve electrical conductivity and transparency via solution processing route, greater insight into the effect of processing and microstructure/defects on the electrical and optical properties is needed. In this work, Al-doped ZnO films were deposited on glass substrates by sol–gel spin coating route. The formation of wurtzite structure was confirmed, and the crystallite size of the films was estimated by X-ray diffraction (XRD) pattern analysis. Greater than 85% transparency in the films was obtained in visible and near IR regime as examined by UV–Vis spectroscopy. An increase in the band gap was observed with increasing Al concentration from 0 to 3 at.%. The electrical properties were evaluated by the Hall measurement, and obtained resistivity was in the order of 10 –2 Ωcm. The presence of defect states and their co-relation with the electrical properties were investigated by photoluminescence spectroscopy and X-ray photoelectron spectroscopy.