Effect of Substrate Temperature on Properties of Copper Oxide Thin Films Coated by Spray Pyrolysis.

Copper oxide shows a wide range of optical as well as electrical characteristics depending upon the preparation parameters. This wide range turning capability makes it a preferable candidate for effective use in various application fields like optical filters, light energy harvesting, gas sensing and semiconducting device fabrication. Spray pyrolysis technique with manual spray system was used to deposit a thin layer of copper oxide on glass substrates at temperatures of 300°C, 350°C, and 400°C. X-ray diffraction analysis shows that all the thin films obtained have monoclinic phase. A change of grain size from 15 nm to 25 nm was observedas the substrate temperature was varied from 300°C to 400°C. The Hall coefficient analysis confirms p-type conductivity in films obtained at 300°C and 350°C and N type conductivity with high resistivity for film coated at 400°C. Optical band gap increases from 1.75 to 2.17 eV with the increase in substrate temperature due to energy band tailing. [ABSTRACT FROM AUTHOR]