Development of the α-IGZO/Ag/α-IGZO Triple-Layer Structure Films for the Application of Transparent Electrode

Abstract

We investigated the structural, optical, and electrical properties of amorphous IGZO/silver/amorphous IGZO (α-IGZO/Ag/α-IGZO) triple-layer structures that were deposited at room temperature on Eagle XG glass and flexible polyethylene terephthalate substrates through the sputtering method. Thin Ag layers with different thicknesses were inserted between two IGZO layers to form a triple-layer structure. Ag was used because of its lower absorption and resistivity. Field emission scanning electron microscopy measurements of the triple-layer structures revealed that the thicknesses of the Ag layers ranged from 13 to 41 nm. The thickness of the Ag layer had a large effect on the electrical and optical properties of the electrodes. The optimum thickness of the Ag metal thin film could be evaluated according to the optical transmittance, electrical conductivity, and figure of merit of the electrode. This study demonstrates that the α-IGZO/Ag/α-IGZO triple-layer transparent electrode can be fabricated with low sheet resistance (4.2 Ω/□) and high optical transmittance (88.1%) at room temperature without postannealing processing on the deposited thin films.

Instantaneous Semiconductor-to-Conductor Transformation of a Transparent Oxide Semiconductor a-InGaZnO at 45 °C

“…We compared the performance of transparent conductive a-IGZO film with other transparent conductors, such as TCOs, ,− TCO/metal multilayers, − , correlated metals, and various nanotube and nanowire assemblies, ,, and plotted against the maximum process temperature at the substrate (Figure ), using the Haacke figure of merit (FOM) shown in eq Here, the average T across the visible spectra (380–750 nm) was used instead of T at 550 nm.…”

“…Wide band gap (transparency) and highly conductive materials used to be an oxymoron. To achieve high conductivity while retaining good transparency, the usual strategy has been to degenerately dope wide-band-gap semiconductors to increase carrier concentration and achieve low effective mass. − This is achieved in the most popular transparent conductive oxide (TCO), Sn-doped In 2 O 3 (indium tin oxide (ITO)), where Sn dopants substitute into the lattice leading to an increased carrier density. , Now, several transparent conductors besides ITO exist, such as thin metal/TCO multilayers, − metal meshes, − conducting polymers, − correlated metals, carbon nanotubes, − and nanowire assemblies. , Thin metal/TCO multilayers or meshes generally have excellent conductivity, but both electrical and optical properties are dependent on thickness (thin metal/TCO multilayers) and spacing (metal meshes). Consequently, a tradeoff exists: reducing the thickness and spacing enhances transparency but degrades conductivity .…”

Advances in Flexible Metallic Transparent Electrodes

“…Data are extracted from literature: graphene, [ 45 ] carbon nanotubes (CNTs) networks, [ 46 ] AgNW networks, [ 47,48 ] ITO, [ 43,49,50 ] metal nanotrough, [ 43,51,52 ] metal grids [ 53–56 ] and oxide/Ag/oxide multilayer structures. [ 57–59 ] The dashed lines fit with iso‐values of the Haacke figure of merit (FoM): 10, 20, 40, 80, 160, 320 (10 −3 Ω −1 ). For data extracted from refs.…”

“…For data extracted from refs. [ 57,59 ], the transmittance values without substrate contribution were estimated with assumption that the bare glass substrate has a total transmittance of 92%.…”

Investigation of SiO2/TiO2 Index Matching Layer Applied to MTO/Ag/MTO Structured Film Deposited on PET Substrate

“…Transparent conductive electrodes (TCEs) are the core components of a variety of optoelectronic devices such as flexible displays, thin film transistors, solar cells, and touch screen panels . Among the different types of TCEs investigated, the oxide/metal/oxide (OMO) structured multilayer films are one of the most promising transparent conducting oxide (TCO) materials for applications requiring flexible TCEs; this is because of the excellent optical and electrical performance of these films in flexible TCEs, as well as their cost effectiveness . Previously, we studied the excellent optical and electrical properties of OMO structured films consisting of manganese (4.04 at.%)‐doped tin oxide (MTO) and silver with different MTO layer thicknesses .…”