Growth behavior and microstructure of CdS thin films deposited by an electrostatic spray assisted vapor deposition (ESAVD) process

Dense and adherent CdS films were successfully deposited onto glass substrates at low temperatures (less than or equal to 450 degreesC) using a novel and cost-effective electrostatic spray assisted vapor deposition process. A mixture of cadmium chloride and thiourea precursors in ethanol/water solvent was used to deposit CdS films in an open atmosphere. The relationship between the field strength and electrostatic spray mode was established. The influences of substrate temperature and precursor flow rate on the microstructure of the films were investigated. The microstructure of the films was examined using a combination of X-ray diffraction, atomic force microscopy and scanning electron microscopy methods. At optimum process conditions, the desirable uniform CdS films with oriented columnar structure were deposited at 400 similar to 420 degreesC at a growth rate of 0.05 mum/min. The relationships between the growth behavior and structure of the films are discussed, and a deposition model for the process is proposed. (C) 2001 Elsevier Science B.V. All rights reserved.