Characterization of the electrical and optical properties for a-IGZO/Ag/a-IGZO triple-layer thin films with different thickness depositions on a curved glass substrate

Abstract

Nine specimens are prepared on the basis of the L9(33) orthogonal array design to evaluate the optical and electrical properties, morphology, and microstructure of a-IGZO/Ag/a-IGZO (IAI) triple-layer composite films deposited on curved glass substrates with a different radius of curvature efficiently. The experiments are arranged for the change in the three controlling factors, namely the IGZO and Ag thicknesses, and the substrate’s radius of curvature. The radius of curvature has the highest contribution for the RMS surface roughness (SRq) and the mean particle size (PS). The carrier mobility (CM) and carrier concentration (CC) are proportional to each, irrespective of the controlling factors in this study. An increase in the radius of curvature can result in the increase of SRq and PS, and therefore brings in a surface scattering effect that can cause the reduction of CM as well as the enhancement of resistivity (R). In addition, a sufficiently large radius of curvature can elevate the transmittance at 550 nm and Haack’s figure of merit (FOM) effectively, but it can also lower the reflectance for blue, green and red. Via the carrier injections, increasing the Ag thickness can elevate the carrier mobility and concentration significantly. The reflectance for blue, green, and red are also risen by increasing the Ag thickness. As a result of the Burstein-Moss effect, carrier concentration and optical bandgap are elevated by increasing the IGZO thickness. Additionally, the reflectance for blue, green, and red are also increased. Appropriate choices in the IGZO and Ag thicknesses and the radius of curvature can obtain the transmittance >80 %, and elevate the FOM significantly.