Electric Field-Assisted Chemical Bath Deposition of ZnO Thin Films: Effects of Field Intensity, Polarity Inversion, and Air Agitation on Film Properties

This study presents an innovative modification to the Chemical Bath Deposition (CBD) method for synthesizing zinc oxide (ZnO) thin films by incorporating a high-voltage electric field (HVEF), with and without electrical polarity inversion, to influence film growth dynamics. Two configurations, CBD-HVEF-A and CBD-HVEF-B, were developed to assess the effects of electric field strength, periodic inversion, air agitation, and solution pH on the structural, morphological, and optical properties of ZnO coatings. X-ray diffraction confirmed the formation of the wurtzite ZnO phase, with reduced interplanar spacing and crystallite size under electric fields, especially when polarity was inverted. Scanning electron microscopy revealed that particle size, shape, and distribution were strongly dependent on synthesis parameters, with electric field and air injection enabling higher surface coverage and finer nanostructures. Optical measurements showed a consistent increase in the band gap (blue shift) and reduced defect-related absorption. These findings demonstrate that controlled electric field application during CBD enables precise tuning of ZnO film properties for advanced optoelectronic applications.