Highly boosted homogeneity of polymer matrix composites filled with MXene-derived 2D titanium oxide nanosheet for high-k gate dielectrics

Polymer-based multilayer films with solution processability and specifically tailored material properties are promising candidates as gate dielectrics in functional electronic devices. The dielectric performance of polymer composites that are formed by incorporating nano-scale ceramic or conductive fillers in a polymer matrix can drastically increase dielectric constants. However, producing these polymer composite dielectrics can be challenging because the dispersion homogeneity of fillers and interfacial adhesion between the filler and the matrix are difficult to control. Therefore, developing an adequately aligned structure of incorporated fillers inside the polymer matrix is strongly demanded. Herein, to achieve concurrent improvements in the dielectric constant and dielectric loss, a rational design process for a multilayer-structured gate dielectric layer based on conductive Ti3C2Tx MXene, ceramic TiO2 and poly(vinyl alcohol) (PVA) is proposed. We present a high-k, pinhole-free, and PVA-based nanocomposite dielectric obtained by assembling two-dimensional MXene into a highly aligned three-dimensional rutile TiO2 aerogel. The homogeneous hybrid nanosheet-dispersed polymeric nanocomposite, which attains an exceptionally high dielectric constant of 66.8 (more than one order of magnitude higher than that of pristine PVA), exhibits a relatively low loss tangent, as low as 10−1. Our approach paves the path for developing high-performance Au/PVA-2D TiO2-MXene/p–Si capacitors comprising nanostructured gate dielectrics fabricated using lightweight hybrid aerogel template-assistance.