Post-Annealing Effects on Surface Morphological, Electrical and Optical Properties of Nanostructured Cr-Doped CdO Thin Films

• Published in: Journal of electronic materials 2018, Vol.47 (1), p.503-511
• Main Authors: Hymavathi, B., Rajesh Kumar, B., Subba Rao, T.
• Format: Article
• Language: English
• Subjects: Annealing; Atomic force microscopy; C band; Characterization and Evaluation of Materials; Chemistry and Materials Science; Direct current; Electrical properties; Electron microscopy; Electronics and Microelectronics; Field emission microscopy; Glass substrates; Hall effect; Instrumentation; Lattice parameters; Magnetron sputtering; Materials research; Materials Science; Nanostructure; Optical and Electronic Materials; Optical properties; Packing density; Porosity; Probe method (forecasting); Solid State Physics; Thin films; Transmittance; X-ray diffraction
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-017-5799-8

Nanostructured Cr-doped CdO thin films were deposited on glass substrates by reactive direct current magnetron sputtering and post-annealed in vacuum from 200°C to 500°C. X-ray diffraction studies confirmed that the films exhibit cubic nature with preferential orientation along the (111) plane. The crystallite size, lattice parameters, unit cell volume and strain in the films were determined from x-ray diffraction analysis. The surface morphology of the films has been characterized by field emission scanning electron microscopy and atomic force microscopy. The electrical properties of the Cr-doped CdO thin films were measured by using a four-probe method and Hall effect system. The lowest electrical resistivity of 2.20 × 10 −4  Ω cm and a maximum optical transmittance of 88% have been obtained for the thin films annealed at 500°C. The optical band gap of the films decreased from 2.77 eV to 2.65 eV with the increase of annealing temperature. The optical constants, packing density and porosity of Cr-doped CdO thin films were also evaluated from the transmittance spectra.