Radio frequency sputtered Al:ZnO-Ag transparent conductor: A plasmonic nanostructure with enhanced optical and electrical properties

Abstract

Optimization of metal-based transparent conductors (MTCs) made of silver and aluminium-doped zinc oxide (AZO) prepared by radio-frequency (r.f.) sputtering has been carried out through tuning of metal film properties. The influence of morphology and related plasmonic features of AZO/Ag/AZO MTCs on their optical and electrical performance is demonstrated and it is shown that the nominal thickness of the silver layer itself is not the most crucial value determining the MTC performance. The MTC performance has been optimized by a search of deposition conditions ensuring fractal-type metal layer formation up to a certain coalescence state that enables full gaining from silver optical properties, including its plasmonic features. For 150 W- and 200 W-deposited silver, MTCs with maximum transmittance as high as 83.6% have been obtained. These coatings have a figure of merit as good as 0.01 Ω−1 and a remarkably wide spectral transparency region: transmittance higher than 70% down to 1200 nm for 200W-samples. Modelling of the MTC coatings is proposed additionally, based on variable angle spectroscopic ellipsometric measurements, which takes into account the variation of the optical properties of silver when deposited in various conditions and embedded in a semiconductor stack.

Diatom frustules decorated with zinc oxide nanoparticles for enhanced optical properties

“…Photoacoustic Spectroscopy (PAS) [14,15] is an extremely versatile, non-destructive technique which allows the optical and thermal analysis of films [16,17], scattering materials [18,19], powders, gels, and recently nanomaterials [20,21], chiral materials [23,24], and metamaterials. It is a more suitable technique, if compared to conventional spectrophotometric ones, to measure the optical properties of nanomaterials and/or scattering media.…”

Spatially Resolved Optoelectronic Properties of Al-Doped Zinc Oxide Thin Films Deposited by Radio-Frequency Magnetron Plasma Sputtering Without Substrate Heating

“…For example, cost effective solar cells based on Cu (In,Ga)Se 2 (CIGS) and Cu 2 ZnSnS 4 (CZTS) absorbers have been fabricated with a TCO based on AZO [6,7]. There are several methods used to deposit AZO, including physical vapor deposition (under various operation conditions for magnetron sputtering, such as radio-frequency [8][9][10][11][12][13][14][15][16][17][18][19][20], medium-frequency [8,[21][22][23][24][25][26], DC [8,16,22,[26][27][28][29][30][31][32][33][34][35][36][37], pulsed DC [38], high power impulse [39,40], ion beam assisted [41], chemical vapor deposition [1,5] and other chemical methods such as spin coating and sol gel [2,4]. Among them, magnetron plasma sputtering has been successfully used to deposit ITO on large area substrates (up to 15 m 2 ) and is also regarded as a viable and cost effective solution for AZO …”

Effect of Silver Dopants on the ZnO Thin Films Prepared by a Radio Frequency Magnetron Co-Sputtering System

“…Silver-doped ZnO (referred to as Ag-ZnO, hereafter) have been synthesized using several technologies, such as photochemical, solvothermal, and pulse laser deposition [ 19 , 20 , 21 ]. It is also acceptable to prepare using sputtering technology, which is widely used in the coating industry [ 22 , 23 ]. In this work, we used a radio frequency (RF) magnetron co-sputtering system, which has the advantage of simple and in situ control on the elemental composition of the resulting film over the conventional sputtering system, to prepare Ag-ZnO co-sputtered films at various Ag atomic ratios.…”