Physical properties of a non-transparent cadmium oxide thick film deposited at low fluence by pulsed laser deposition

•A non-transparent cadmium oxide film has been deposited by pulsed laser deposition.•The CdO film is polycrystalline and highly oriented in the (2 0 0) direction.•Thermal treatment was applied in order to see the effect on its physical properties.

A stable non-transparent CdO film was grown by pulsed laser deposition. The sample was thermally annealed at 500 °C in air. A (2 0 0) highly oriented polycrystalline film was obtained. The annealed sample has not preferred orientation. Scanning electron micrographs show a grain size reduction for the annealed sample. By Raman spectroscopy, the defects related second order vibrational modes of CdO were observed. Chemical composition analysis shows the presence of CdO together with a substoichiometric CdOx phase for the as-grown sample. For the annealed sample a compensation of oxygen vacancies was observed. Electrical resistivity measurements give a value of 8.602 × 10−4 (Ω cm) for the as-grown film. For the annealed sample the electrical resistivity increased to a value of 9.996 × 10−3 (Ω cm). Zero transmission has never been reported for CdO films. The photoluminescence spectra were measured in order to shed some light on the origin of the zero transmission.

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