Effects of Grain Size on the UV-Photoresponse of Zinc Oxide Thin Films Grown by Spray-Pyrolysis

PARRA, RODRIGO; ALDAO, CELSO M.; RAMAJO, LEANDRO A.; VILLEGAS, EDGAR A.; SAVU, RALUCA

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE

WILEY-V C H VERLAG GMBH

Año: 2018 vol. 215

1862-6300

Zinc oxide films with different average grain size are deposited on glasssubstrates by spray-pyrolysis at 425°C. Samples are characterized by XRD,UV?Vis transmittance, FE-SEM, and electrical properties measurements. Theincrease in conductivity observed under 365 nm wavelength illumination isevaluated in terms of grain size. Films with small grains (120 nm) showhigher response with respect to films with larger grains (230 and 300 nm). Amodel considering resistivity and grain size for the prediction of the responseof films in terms of UV-to-dark conductivity ratio is proposed and validatedwith experimental results.