Growth temperature-driven optimization of optoelectronic and thermoelectronic performance in In-doped ZnO films

Abstract This study examines the impact of substrate temperature on In-doped ZnO thin films were created on glass substrates via the RF-magnetron reactive sputtering method. The results indicate that the thin films possess a hexagonal Wurtzite structure, preferentially oriented along the (002) plane, which is perpendicular to the substrate surface. The crystallite sizes increases from 32.10 nm to 35.24 nm with an increase in substrate temperature. The UV–Vis transmission spectrum indicates that the films have an average transmittance over 85% in the visible light spectrum. The optical bandgap energy was measured via the Tauc method, ranging from 3.44 eV to 3.52 eV. Hall effect experiments indicate that the films exhibit low resistivity (∼10 −4 Ω·cm), high carrier concentration exceeding 10 21 cm −3 , and electron mobility ranging from 3.03 to 6.72 cm 2 ·V −1 ·s −1 . The figure of Merit varies from 1.17 × 10 −2 to 2.85 × 10 −2 Ω −1 , with the sample deposited at 250 °C achieving the maximum Seebeck coefficient (40.25 μV·K −1 ) and the ideal power factor (253.13 μW·m −1 ·K −2 ). These findings support the application of IZO thin films in optoelectronic and thermoelectric applications, with the goal of developing advanced technology based on environmentally friendly oxide materials.