An influence of deposition temperature on structural, optical and electrical properties of sprayed ZnO thin films of identical thickness

•The ZnO films exhibit highest transmittance (95%) and lowest resistivity (0.011 Ω-cm).•Higher Ts add to grain size (31 -60 nm) which shifts the Eg (3.272 -3.242 eV).•At higher Ts electrical conductivity rises due to desorption of chemisorbed oxygen.•The hydrophobicity increases with rise in Ts due to growth of ZnO nanorods.

Nanocrystalline ZnO thin films were deposited at different temperatures (Ts = 325 °C–500 °C) by intermittent spray pyrolysis technique. The thickness (300 ± 10 nm) independent effect of Ts on physical properties was explored. X-Ray diffraction analysis revealed the growth of wurtzite type polycrystalline ZnO films with dominant c-axis orientation along [002] direction. The crystallite size increased (31 nm–60 nm) and optical band-gap energy decreased (3.272 eV–3.242 eV) due to rise in Ts. Scanning electron microscopic analysis of films deposited at 450 °C confirmed uniform growth of vertically aligned ZnO nanorods. The films deposited at higher Ts demonstrated increased hydrophobic behavior. These films exhibited high transmittance (>91%), low dark resistivity (∼10−2 Ω-cm), superior figure of merit (∼10−3 Ω−1) and low sheet resistance (∼102 Ω/□). The charge carrier concentration (η -/cm3) and mobility (μ – cm2V−1s−1) are primarily governed by crystallinity, grain boundary passivation and oxygen desorption effects.

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