Effects of annealing on the optical and electrical properties of CdO thin films prepared by thermal evaporation

Abstract

Cadmium oxide (CdO) thin films with a thickness of approximately 298nm were prepared on glass substrates at room temperature via thermal evaporation technique in vacuum (∼2.2×10−5mbar). X-ray diffraction results show that the films were polycrystalline structure and had a cubic crystal. CdO thin films and peaks became more crystalline and sharp after annealing at 500°C for 1h. The optical direct band gap energy was determined by optical absorption using an UV/vis spectrophotometer. The band gap energy was 2.48eV before annealing, and slightly decreased to 2.42eV after annealing. Electrical measurement results show that the resistivity decreased with increasing carrier concentration after annealing. Hall-effect measurement results reveal that all of the thin films were n-type.