Improved properties of spray pyrolysed CuO nanocrystalline thin films

Abstract

CuO thin films prepared by spray pyrolysis method has wide range of applications. CuO thin films were coated on glass substrate at various temperatures such as 250, 350, 400, and 500 °C by spray pyrolysis. Thin films prepared were characterized by various techniques such as X-ray diffraction, SEM, UV–visible spectroscopy, PL and Hall measurements. XRD diffraction patterns reveal that the films are polycrystalline in nature exhibiting monoclinic structure. The prominent peak corresponds to (200) plane and the corresponding calculated crystallite size varies from 4 to 7 nm. SEM images exhibit grains of uniform size. It is found that the optical absorbance decreases with the increase in temperature and the optical energy band gaps vary from 2.22 to 2.75 eV for various substrate temperatures. Electrical studies done using Hall measurement system show that the copper oxide films are p-type semiconductors with carrier concentration in the order of 1016 cm−3. The electrical resistivity of the copper oxide films obtained was in the range 3.689 × 10−3 to 8.538 × 10−3 Ω cm. Hence, the CuO film is suitable for solar cell applications.