Low-temperature, high-performance solution-processed metal oxide thin-film transistors formed by a ‘sol–gel on chip’ process

Abstract

At present there is no ‘ideal’ thin-film transistor technology for demanding display applications, such as organic light-emitting diode displays, that allows combining the low-temperature, solution-processability offered by organic semiconductors with the high level of performance achievable with microcrystalline silicon1. N-type amorphous mixed metal oxide semiconductors, such as ternary oxides Mx1My2Oz, where M1 and M2 are metals such as In, Ga, Sn, or Zn, have recently gained momentum because of their high carrier mobility and stability2, 3 and good optical transparency, but they are mostly deposited by sputtering. So far no route is available for forming high-performance mixed oxide materials from solution at low process temperatures <250 °C. Ionic mixed metal oxides should in principle be ideal candidates for solution-processable materials because the conduction band states derived from metal s-orbitals are relatively insensitive to the presence of structural disorder and high charge carrier mobilities are achievable in amorphous structures2. Here we report the formation of amorphous metal oxide semiconducting thin-films using a ‘sol–gel on chip’ hydrolysis approach from soluble metal alkoxide precursors, which affords unprecedented high field-effect mobilities of 10 cm2 V−1 s−1, reproducible and stable turn-on voltages Von≈0 V and high operational stability at maximum process temperatures as low as 230 °C.

High Electron Mobility Thin‐Film Transistors Based on Solution‐Processed Semiconducting Metal Oxide Heterojunctions and Quasi‐Superlattices

“…Unlike conventional a‐IGZO TFTs,45, 46 here we use binary metal oxides for each layer in the stacked structures. This strategy helps to avoid complex and in some cases unwanted chemical interactions between different precursor molecules that are generally known to degrade the electrical performance of solution‐processed oxide TFTs 4, 30, 47…”

“…Because of the latter requirement it is not a trivial question whether high‐quality oxide heterointerfaces can be realized using simpler, cost‐efficient, and high‐throughput fabrication methods that are compatible with existing semiconductor fabrication processes (e.g., solution‐based) and even perhaps temperature‐sensitive substrate materials such as plastic. Thus, the development of ease to implement metal oxide hetero/multilayer structures could help overcoming important bottlenecks associated with the level of performance and manufacturing of incumbent TFT technologies, and enable the emergence of a host of large‐area, flexible optoelectronics 4, 26, 27, 28, 29, 30…”

An ‘aqueous route’ for the fabrication of low-temperature-processable oxide flexible transparent thin-film transistors on plastic substrates

“…[10][11][12] A few studies on low-temperatureprocessable MOSs have been reported. [13][14][15][16] However, the authors of these studies used either complex and unstable precursors that required significant effort and multiple steps for synthesis or complicated chemical reactions that are not appropriate for the general fabrication technique. Although methods based on nanostructures, nanoparticles, nanorods or carbon-related materials also allow low-temperature deposition, concerns about the uniformity of the resulting devices related to the uncontrollable distribution of nanosized materials still remain.…”

Carbon-decorated iron oxide hollow granules formed using a silk fibrous template: lithium-oxygen battery and wastewater treatment applications

“…The O 1s peak at higher binding energy (532.0 eV) is associated with chemisorbed or dissociated oxygen or OH species, such as adsorbed H 2 O or O 2 adsorbed on the surface of the materials. 34 In particular, absorption of water on the surface of the air cathode results in an undesirable effect in Li-O 2 batteries. 35 The content of oxygen vacancies in the C/Fe 3 O 4 HGs was higher than that in the Fe 2 O 3 HGs.…”