Direct Photopatterning of Solution–Processed Amorphous Indium Zinc Oxide and Zinc Tin Oxide Semiconductors—A Chimie Douce Molecular Precursor Approach to Thin Film Electronic Oxides

Abstract

AbstractDirect photopatterning of indium zinc oxide (IZO) and zinc tin oxide (ZTO) semiconductors is realized using Schiff‐base complexes of indium, zinc, and tin(II) with methoxyiminopropionato ligands as precursors. These precursor complexes are stable under visible light, but they interestingly decompose in the UV region, thereby facilitating a site‐selective photopatterning and its subsequent conversion to the desired amorphous oxides. Thin film transistors (TFTs) with photopatterned IZO and ZTO layers exhibit high performance after post‐annealing at relatively low temperatures between 250 and 350 °C, with charge‐carrier mobilities (µsat) of 7.8 and 3.6 cm2 (V s)−1 for IZO and ZTO, respectively. The mechanism of the photodecomposition of the precursor films is studied by attenuated total reflectance–Infrared spectroscopy. Apart from the electrical characterization, the resultant UV‐patterned oxide thin films are characterized by transmission electron microscopy micrographs of focussed ion beam (FIB)‐prepared cross sections, atomic force microscopy, as well as Auger depth profiles. X‐ray photoelectron spectroscopy investigations elucidate the influence of surface hydroxylation on the TFT performance. The straightforward approach of facile precursor UV‐photopatterning demonstrates its potential feasibility as a low‐cost method toward integration of such solution–processed oxide films into large‐area electronics.