Influence of Thermal Process on Physical Properties of ZnO Films Prepared by Spray Pyrolysis

Abstract

ZnO lms were deposited on glass substrates by ultrasonic spray pyrolysis technique at a substrate temperature of 300±5 ◦C. All of the lms have been annealed at 500 ◦C temperature for di erent time (1, 2, and 3 h) to improve the optical, electrical and surface properties. The e ect of annealing time on the lms of physical properties has been investigated. UV-Vis spectrophotometer has been used for transmittance measurements. Also, band gap values of the lms have been determined by optical method. Atomic force microscopy has been used to have information the surface morphology and roughness values of the lms. Thicknesses, refractive index and extinction coe cient values of the lms have been determined by spectroscopic ellipsometry technique. The electrical conduction mechanisms and resistivity of the lms were investigated using two probe technique. After all the investigations it was concluded that annealing time has a dramatic e ect especially on the surface, optical properties and electrical resistivity values of ZnO lms. From the results of these investigations, the application potential of the lms for solar cell devices as transparent electrode was searched.