Nano-viewpoint in Modeling and Investigation of the D/M/D Transparent-Conductive Layer

Gholamhosain Haidari

doi:10.1007/s11468-021-01523-5

Abstract

A transparent-conductive film (TCF) is widely used in various electro-optical devices. The dielectric/metal/dielectric (D/M/D) as one type of TCF has been highly considered due to more advantages, such as the possibility of selecting different materials and engineering other properties. For pre-fabrication design, it is often modeled with a 1D photonic crystal. This model needs to be improved due to the low thickness of the metal layer since a very thin metallic layer leads to a nanostructure instead of a uniform layer. In this study, after proper nanostructure modeling, the 3D-FDTD method was used to simulate different optical properties of the structure. The first aspect of the importance of the nanostructured model is to address the serious plasmonic losses. They are associated with the complicated metallic form in D/M/D that is not considered in conventional modeling. The simulation results showed that for Ag, plasmonic loss peaks demonstrate a wide distribution over the visible spectrum. These peaks show a more significant distribution near the UV–visible border for Al nanostructure. In both, the behavior of optical plasmonic loss tends to redshift compared to their bulk plasmonic peaks. Concerning optical transmission, Al does not offer a notable advantage over Ag. Due to the intense excitation of plasmonic modes when the metal layer has pores, a layer of entirely connected nanoparticles with the least possible thickness can have the desired optical properties. The increased rough surface of the dielectric layer due to the nanostructured metallic layer was also modeled.

Highlights

Transparent conductive films (TCF) are transparent and conductive thin layers
Pre-fabrication designs are usually based on the 1D photonic crystal that this selected model does not conform to the experimental fabrication characteristics
3D-finite-difference time-domain (FDTD) modeling was performed based on the nanotechnology viewpoint of the metallic layer

Summary

Introduction

Transparent conductive films (TCF) are transparent and conductive thin layers. They are an essential component in various optoelectronic components such as liquid crystal displays, OLEDs, touch screens, and photovoltaics [1, 2]. For TCF, a metal oxide layer using indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and doped zinc oxide is usually used [2]. Determining the thickness of the metal layer is one of the significant design challenges of this structure. The Volmer-Weber happens with low wettability materials forms isolated islands This method is the typical growth accessible by soft metals (like Ag) onto insulators [16]. In a few studies for designing the D/M/D, the FDTD method has been used, but the assumption of uniform layers has remained. Those results can be achieved with TMM, too [18, 19]. The change of metal material from Ag to Al and the effect of adding surface roughness to the nano-based modeling were investigated

Modeling Method - Simulation

Nanostructure viewpoint

And Discussion

Conclusion