Unveiling the evolution of microstructural and optoelectronic properties of spray‐pyrolyzed ZnO thin films via tailoring the aerosol deposition time

ZnO thin films with diverse thicknesses were deposited via the spray pyrolysis technique by varying the deposition time ( τ ). The XRD analysis shows an increase in polycrystallinity for films with an increase in τ ; however, all films exhibit predominant growth along the c ‐axis [002] direction. The FE‐SEM analysis shows the growth of well‐aligned ZnO nanorods upright on the substrate at τ = 20 min. EDS analysis confirms the high quality ZnO film formation with a slightly rich oxygen concentration. The films exhibit optical transmittance >90%, with the highest of 95% when deposited for 24 min. There is a rise in crystallite size along with film thickness; however, bandgap energy ( E g ) declines with a rise in τ . The inverse relation of E g with Urbach energy ( E u ) is attributed to superior crystallinity at lower E u . Under optimal deposition time τ = 20 min, the film shows the highest dark conductivity 108.2 S/cm, free electron concentration η = 3.76 × 10 19 /cm 3 , and mobility μ = 17.98 cm 2 V −1 s −1 . For τ = 20 min, the film exhibits the best figure of merit, Φ TC‐H = 2.03 × 10 −3 Ω −1 , Φ TC‐H‐HR = 4.11 × 10 −2 Ω −1/12 , and the least sheet resistance, R s = 275 Ω/□.