Influence of In doping on the structural, optical and acetone sensing properties of ZnO nanoparticulate thin films

• Published in: Materials science in semiconductor processing 2013-02, Vol.16 (1), p.200-210
• Main Authors: Prajapati, C.S., Sahay, P.P.
• Format: Article
• Language: English
• Subjects: Acetone; Acetone sensing properties; Applied sciences; Cross-disciplinary physics: materials science; rheology; Doping; Electronics; Exact sciences and technology; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Nanomaterials; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Operating temperature; Optoelectronic devices; Physics; Production techniques; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Spray coating techniques; Structural and optical properties; Surface chemistry; Surface treatment; Thin films; Zinc oxide; ZnO nanoparticulate thin films
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2012.04.015

Indium-doped zinc oxide (ZnO) nanoparticle thin films were deposited on cleaned glass substrates by spray pyrolysis technique using zinc acetate dihydrate [Zn(CH3COO)2 2H2O] as a host precursor and indium chloride (InCl3) as a dopant precursor. X-ray diffraction results show that all films are polycrystalline zinc oxide having hexagonal wurtzite structure. Upon In doping, the films exhibit reduced crystallinity as compared with the undoped film. The optical studies reveal that the samples have an optical band gap in the range 3.23–3.27eV. Unlike the undoped film, the In-doped films have been found to have the normal dispersion for the wavelength range 450–550nm. Among all the films investigated, the 1at% In-doped film shows the maximum response 96.8% to 100ppm of acetone in air at the operating temperature of 300°C. Even at a lower concentration of 25ppm, the response to acetone in this film has been found to be more than 90% at 300°C, which is attributed to the smaller crystallite size of the film, leading to sufficient adsorption of the atmospheric oxygen on the film surface at the operating temperature of 300°C. Furthermore, In-doped films show the faster response and recovery at higher operating temperatures. A possible reaction mechanism of acetone sensing has been explained.