Effect of substrate temperature on the stability of transparent conducting cobalt doped ZnO thin films

Abstract

Transparent conducting Co doped ZnO thin films have been fabricated by Ultrasonic spray. The thin films were deposited at three different substrate temperatures of 300, 350 and 400 ℃. The obtained films had a hexagonal wurtzite structure with a strong (002) preferred orientation. The maximum crystallite size value of the film deposited at 350 ℃ is 55.46 nm. Spectrophotometer (UV-vis) of a Co doped ZnO film deposited at 350 ℃ shows an average transmittance of about 90%. The band gap energy increased from 3.351 to 3.362 eV when the substrate temperature increased from 300 to 350 ℃. The electrical conductivity of the films deposited at 300, 350 and 400 ℃ were 7.424, 7.547 and 6.743 (Ω·cm)-1 respectively. The maximum activation energy value of the films at 350 ℃ was 1.28 eV, indicating that the films exhibit a n-type semiconducting nature.