Influence of deposition parameters and heat treatment on the NO2 sensing properties of nanostructured indium tin oxide thin film

• Published in: Thin solid films Vol. 519; no. 10; pp. 3378 - 3382
• Main Authors: VIJAYALAKSHMI, K, RAVIDHAS, C, VASANTHI PILLAY, V, GOPALAKRISHNA, D
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.03.2011
• Subjects: Annealing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Deposition by sputtering; Detection; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Indium tin oxide; Magnetron sputtering; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nitrogen dioxide; Other topics in nanoscale materials and structures; Partial pressure; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Scanning electron microscopy; Annealing; Electrical properties; Indium tin oxide; Surface morphology; Hall effect; Crystallinity; XRD; Nanostructures; Coatings; Indium oxide; Heat treatments; Sputtering; Thin films; Partial pressure; Tin oxide; Physical vapor deposition; Electric resistivity; Absorption spectra; Surface area; Nitrogen dioxide; Gas sensors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.12.164

Highly oriented and transparent indium tin oxide (ITO) films have been deposited onto glass substrates by radio frequency magnetron sputtering at 648K, under an oxygen partial pressure of 1Pa. The effect of the sputtering power and annealing was studied. Transmission was measured with a double beam spectrometer and electrical analysis using four probe and Hall effect setup. Structural characterization of the films was done by X-ray diffraction. Characterization of the coatings revealed an electrical resistivity below 6.5A-10a degree 3 I[copycm. The ITO films deposited at 648K were amorphous, while the crystallinity improved after annealing at 700K. The optical transmittance of the film was more than 80% in the visible region. The surface morphology examined by scanning electron microscopy appears to be uniform over the entire surface area, after annealing. The NO2 sensing properties of the ITO films were investigated. At a working temperature of 600K, the ITO sensor showed high sensitivity to NO2 gas, at concentrations lower than 50ppm.