Tuning of optical and electrical properties of transparent conducting AgInO2 thin films by compositional variations

The possibility of combining both optical transparency and electrical conductivity in the same material makes the transparent conducting oxides one of the most sought materials in transparent electronics and other applications. Through a two-stage process involving vacuum evaporation and followed by air annealing, the crystalline delafossite silver indium oxide (AgInO2) thin films are prepared at a substrate temperature ~ 623 K and a pressure ~ 10−5 mbar. The effect of composition on the properties of AgInO2 thin films is studied by preparing silver (Ag)-rich and silver-deficient/In-rich films. X-ray diffraction for structural characterization combined with energy dispersive analysis of X-rays for composition assessment confirms the formation of crystalline thin films with the rhomb-centered rhombohedral delafossite crystalline lattice. The band gap of these films is tuned by varying the amount of indium and silver in these films. Because the band gap energy of the as prepared thin films vary from 3.59 to 3.66 eV as amount of silver increases. Indium-rich thin films show better transparency and conductivity over silver-rich thin films and are better candidates for transparent electronics applications and in UV absorbers.