Electrical and optical properties of polycrystalline CdO thin films

Electrical and optical properties of polycrystalline CdO thin films are discussed. The preparation conditions (substrate temperature, oxidation procedure, and deposition rate) strongly influence the structure, transport and optical properties of films. For CdO thin films deposited onto unheated substrates, the optical transmission is small, but after the heat treatment the optical transmission becomes significant. The CdO thin films deposited onto heated substrates are characterized by high transmission (over 85%). It is found that if after the first heating/cooling cycle the film is maintained in open atmosphere for 24h, the electrical conductivity becomes equal to its value before heat treatment.