Surface morphology characterisation of Sn-doped ZnO films for antireflective coating

Sn-doped ZnO (x=0·0, 0·05, 0·10 and 0·15) films as antireflective coating (ARC) were successfully synthesised by electron beam evaporation method. X-ray diffraction (XRD) analysis confirmed that the as deposited films were hexagonal crystal structure of ZnO which is deteriorated by Sn dopant addition. Investigation of surface roughness films by atomic force microscopy (AFM) showed an increasing surface roughness with increasing dopant concentration. A dopant concentration of 15 at.-% would result in films with 35 nm average roughness (Ra). Annealing at 550°C would drastically increase Ra value especially for heavy doped samples. For 10 and 15 at.-% dopants, the Ra values were 120 and 370 nm. Scanning electron microscopy (SEM) showed that aggregation of small particles occurred more in doped films than in undoped films.