A combinatorial study on ZnO-In2O3-SnO2 system: The effects of different postgrowth annealing conditions on optical and electrical properties

Abstract

ZnO-In2O3-SnO2 (ZITO) thin film library was produced via the combinatorial approach. The films were deposited using a magnetron sputtering system. Varying ZITO compositions were obtained in a single deposition run by employing a custom-made triangular type of substrate carrier magazine. The effect of various postgrowth annealing atmospheres on the electrical and optical properties of the films were ex-amined. Air, Ar, forming gas (Ar+4 vol% H-2), and successive annealing under forming gas + argon atmo-spheres were studied. Room temperature (RT) deposited films were identified either crystalline or amorphous depending on the location of the substrate on the holder. All these samples exhibited average visible transmittance (T-vis) below 75 % and sheet resistance (R-S) higher than 50 S2/? . Annealing under air atmosphere improved the optical and electrical properties of the films significantly, but not simultaneously for the same composition. Although better optical improvement was achieved by annealing under Ar and increase in electrical conductivity after annealing under forming gas, optimum properties have been ob-tained with the latter condition. T-vis values above 85 % and R-S values below 50 S2/? were attained. On the other hand, successive annealing did not provide any advantage in reaching optimal samples when com-pared to single gas atmosphere annealings. Further, increasing the annealing temperature were found to be beneficial particularly for the conductivity of many compositions. Finally, this study has introduced a systematic approach to produce transparent conductive oxide thin films with reduced indium content that can be suitable for many optoelectronic applications. (C) 2022 Published by Elsevier B.V.