Study of the doping of thermally evaporated zinc oxide thin films with indium and indium oxide

The present paper reports observations made on investigations carried out to study structural, optical and electrical properties of thermally evaporated ZnO thin films and their modulations on doping with metallic indium and indium oxide separately. ZnO thin film in the undoped state is found to have a very good conductivity of 90 Ω–1 cm–1 with an excellent transmittance of up to 90 % in the visible region. After doping with metallic indium, the conductivity of the film is found to be 580 Ω–1 cm–1, whereas the conductivity of indium oxide-doped films is increased up to 3.5 × 103 Ω–1 cm–1. Further, the optical band gap of the ZnO thin film is widened from 3.26 to 3.3 eV when doped with indium oxide and with metallic indium it decreases to 3.2 eV. There is no considerable change in the transmittance of the films after doping. All undoped and doped films were amorphous in nature with smooth and flat surface without significant modifications due to doping.