Novel Control of the Synthesis and Band Gap of Zinc Aluminate (ZnAl₂O₄) by Using a DC/RF Sputtering Technique

Zinc aluminate (ZnAl₂O₄) thin films have been deposited through direct current/radio frequency (DC/RF) magnetron sputtering by varying the applied power of an Aluminum (Al) target. The X-ray diffraction (XRD) pattern showed the formation of monophase ZnAl₂O₄ with spinel structure. Moreover, structural analysis like grain size, dislocation density, and lattice strain was calculated through the XRD obtained data. The surface morphological analysis through field emission scanning electron microscopy (FESEM) confirmed the formation of nano-size spinel ZnAl₂O₄. The transmittance of the ZnAl₂O₄ thin film was found to be dependent on the aluminum (Al) target power. An inverse relation was noticed between the transmittance and the Al-power. The optical band gap dependent refractive index, high-frequency dielectric, and static dielectric constant were calculated. [Figure not available: see fulltext.].