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

Direct 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.

Photonic curing of solution-deposited ZrO2 dielectric on PEN: a path towards high-throughput processing of oxide electronics

“…Thus, solution-combustion synthesis alone is inadequate for making oxide electronics on low-temperature polymer substrates, such as polyethylene terephthalate (PET, 150°C) and polyethylene naphthalate (PEN, 220°C) 22 . UV-assisted annealing, on the other hand, uses energy from UV light to reduce the thermal energy needed for oxide formation [23][24][25][26][27][28][29][30][31][32] . This photochemical processing takes advantage of the absorption of UV light by oxide precursors, facilitating precursor decomposition and formation of metal-oxide bonds 24,26,30,33 .…”

Optimization of Transistor Characteristics and Charge Transport in Solution Processed ZnO Thin Films Grown from Zinc Neodecanoate

“…Additionally, its nontoxicity, high electron mobility and stability makes it an attractive candidate for a variety of functional applications [5,6]. Moreover, its suitability as matrix material for doping with number of elements such as aluminium [7], indium [3,[8][9][10][11], gallium [3,9,10], tin [11][12][13], magnesium [14] allows for modulation of its properties. This has resulted in ZnO being utilized for a number of applications such as gas sensing [15][16][17][18], photovoltaics [14,19], UV photodetectors [20][21][22], non-volatile memories [23][24][25], and piezoelectric generators [18,19,26].…”

“…Hence, precursor materials like zinc acetate [5,6,9,12,17] and zinc nitrate [9,32,34] have been widely utilized to obtain ZnO films by decomposing the precursors. In addition to this a number of novel processing chemistry based on combustion synthesis [13,38], metal alkoxide precursor [10], single source tailored organo-complex precursors [39,40] and photosensitive precursors [11,12,41,42] have also been demonstrated to exhibit excellent performance in metal oxide devices. Towards this end, we explore the usability of non-aqueous precursor zinc neodecanoate, referred henceforth as Zn(NDN), as a novel precursor material for ZnO based electronics with further prospects of fabrication steps being compatible with nanoscale directwriting through electron-beam exposure [43,44].…”

Synthesis, oxide formation, properties and thin film transistor properties of yttrium and aluminium oxide thin films employing a molecular-based precursor route

“…For the fabrication of the TFT device an indium zinc oxide (IZO) semiconductor was introduced by employing established oximato precursor compounds, previously reported by our group. 22,[34][35][36] Solutions of the respective indium and zinc precursors were prepared by dissolving 1 wt% in 2-methoxyethanol (ratio In : Zn, 6 : 4), spin-coated at 2500 rpm for 20 seconds onto the Y x O y -(1)-350 dielectric and subsequently annealed at 350 C. Performing of three iterations of the coating procedure results in a lm thickness of $12 nm.…”

“…The IZO precursor solution was generated by using single source zinc and indium precursors as described by us. 22,[34][35][36] A schematic representation of the TFT architecture is shown in Fig. S18 ESI.…”