Decomposition mechanism of indium oxide nanoparticles sandwiched between zinc oxide layers by energetic ions

Decomposition of indium oxide nanoparticles (IONPs) sandwiched between zinc oxide (ZnO) thin films by energetic ions is reported. Multi-layers thin films were deposited using RF magnetron sputtering at room temperature, consisting two thin indium oxide layers sandwiched between three ZnO layers. Films exhibit very high transparency in the visible region. A sharp near band edge absorption with exciton absorption peak in the film annealed at the highest temperature was also observed. The structural and optical properties reveal that the as-deposited films show the formation of IONPs around the interface, which further grow upon increasing in annealing temperature. However, irradiation induces the decomposition of IONPs for the possible formation of single phase indium doped ZnO (IZO). The mechanism of the decomposition of IONPs is understood by the creation of ion tracks in IO. The track radius (Re) of 5.9 nm is calculated in the framework of thermal spike model. Therefore, the IONPs with diameter≤2Re decomposed or amorphized between the crystalline ZnO layers; while the IONPs with diameter>2Re show reduction in size by the electronic sputtering from the IONPs surface under the thermo-elastic effects.