Structural, optical and electrical properties of cadmium zinc oxide films for light emitting devices

Structural, optical and electrical properties of CdyZn1-yO (y=0–0.1) ternary alloy thin films have been investigated for the films prepared using the spin coating method on the glass substrate. XRD pattern confirmed the nano-size polycrystalline hexagonal wurtzite structure for all the samples. The size of nano-crystals was found to be varied in between 21 and 30 nm. Optical band gap calculated from the absorption coefficient signifies the shift in direct band gap from 3.2 to 2.97 eV with cadmium composition. Through EDAX spectrum, it was confirmed that Cadmium was successfully incorporated into ZnO. SEM studies make clear that even after Cadmium incorporation, the surface morphology of the films remained smooth. The current–voltage characteristics obtained from semiconductor characterization system reveals that resistance of the films was found to be decreased with the increase in cadmium composition. Our investigations lead to the applicability of CdZnO as an active layer in CdZnO/ZnO heterostructure for light emitting devices.

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► Properties of CdyZn1-yO (y=0–0.1) ternary alloy have been investigated.
► Optical direct band gap showed shift from 3.2 to 2.97 eV with cadmium composition.
► Our results reveal decrease in the resistance with increase in cadmium composition.