A structural, optical and electrical comparison between physical vapour deposition and slot-die deposition of Al:ZnO (AZO)

Abstract

Aluminium-doped zinc oxide (AZO) is a potential low-cost alternative to indium tin oxide (ITO) for application in optoelectronic devices as a transparent conducting thin film. Typically, AZO thin films are deposited using expensive, high vacuum equipment with high energy cost and materials wastage. In this study, slot-die coating was used as an inexpensive alternative to vacuum deposition to form AZO nanoparticle thin films under ambient laboratory conditions. The films were characterised structurally, optically and electrically and compared with a commercially obtained AZO film fabricated using physical vapour deposition (PVD). Structural characterisation of the nanoparticle film shows uniform coverage across the substrate with increased crystal quality following annealing in Ar up to 500 ^{circ }C. The optical properties of the nanoparticle film exhibit a wider band gap than the PVD film, while the high density of grain boundary defects between the nanoparticles inhibits sheet conductivity.Graphical abstract