Synthesis and optical properties of ZnO nanocluster porous films deposited by modified SILAR method

Ultrasonic rinsing procedure was introduced to successive ionic layer adsorption and reaction (SILAR) method. ZnO nanocluster porous films were successfully deposited on glass substrate using zinc-ammonia complexed precursor. The crystallinity, microstructure, optical properties and photoluminescence were measured and analyzed for both as-deposited and annealed films. Effects of experimental parameters and heat treatment on the structural and optical properties were discussed. Results show that as-deposited ZnO film exhibits excellent crystallinity with the preferential orientation of (0 0 2) plane. A porous feature with interconnected particles of 200-400 nm in ZnO films was observed, with each ZnO particle formed by the aggregation of many crystallites in size of 30-50 nm. The low transmittance due to scattering losses over the porous ZnO layer down to 16% was detected. The annealing at 400 degreesC can promote the preferential orientation along (1 0 0) plane, the interfusion of adjacent particles and the reduction of scattering loss. Intense and sharp ultraviolet emission peaks at 392 mn dominates the PL spectra for both as-deposited and annealed samples, indicating the good optical quality of ZnO layer. (C) 2004 Elsevier B.V. All rights reserved.