Thickness Dependence of FTO Over-Layer on Properties of FTO/FZO Bilayer

Abstract

To realize transparent conducting oxide (TCO) films with the combined desirable characteristics of both SnO2 and ZnO, SnO2:F/ZnO:F bilayered thin films were fabricated with varying thickness of over-layer using a simplified spray pyrolysis technique. The electrical studies revealed that the bilayered films exhibit lesser sheet resistance (Rsh) than the single layered FZO and FTO films. The optical transmittance of FTO/FZO bilayers is around 80% with sharp absorption edge, which makes them suitable candidates for opto-electronic applications. The X-ray diffraction (XRD) patterns of bilayered films showed that in the case of lower thickness FTO over-layers, (002) plane of ZnO phase had the highest intensity, whereas the predominancy was changed in favor of (110) plane of SnO2 phase for higher thickness FTO over-layers. The XRD patterns also revealed that bilayered films have better crystalline nature when compared with the bare FTO films which is confirmed also by the photoluminescence study.