Atomically Thin Antimony‐Doped Indium Oxide Nanosheets for Optoelectronics

Abstract

Wide bandgap semiconducting oxides are emerging as potential 2D materials for transparent electronics and optoelectronics. This fuels the quest for discovering new 2D metal oxides with ultrahigh transparency and high mobility. While the former can be achieved by reducing the thickness of oxide films to only a few nanometers, the latter is more commonly realized by intentional doping. This article reports a one‐step synthesis of few‐unit‐cell‐thick and laterally large antimony‐doped indium oxide (IAO). The doping process occurs spontaneously when the oxide is grown on the surface of a molten Sb–In alloy and 2D IAO nanosheets can be easily printed onto desired substrates. With thicknesses at the atomic scale, these materials exhibit excellent transparency exceeding 98% across the visible and near‐infrared range. Field‐effect transistors based on low‐doped IAO nanosheets reveal a high electron mobility of ≈40 cm2 V−1 s−1. Additionally, a notable photoresponse is observed in 2D IAO‐based photodetectors under ultraviolet (UV) radiation. Photoresponsivities of low‐doped and highly doped IAO at a wavelength of 285 nm are found to be 1.2 × 103 and 0.7 × 103 A W−1, respectively, identifying these materials as promising candidates for the fabrication of high‐performance optoelectronics in the UV region.

Heterojunction Transistors Printed via Instantaneous Oxidation of Liquid Metals

“…Since the introduction of liquid metal surface oxide synthesis by Zavabeti et al. in 2017, In 2 O 3 , HfO 2 , Al 2 O 3 , Ga 2 O 3 , SnO, TeO 2 , ITO, IAO and IZO have been demonstrated via liquid metal printing to fabricate TFTs, UV photodetectors, gas sensors, inverters, amplifiers, dielectrics, and touch capacitive sensors. ,,,− …”

“…To put the results of this study in context as a scheme for rapid fabrication of high mobility transistors, Figure highlights the processing time, temperature, and resulting TFT mobility of liquid metal printing compared with ALD, sol–gel processing, and sputtering. ,− ,,,− LMP is compatible with ultrarapid processing times (<6 s) when compared to the other three methods, but offers the ability to form high mobility (μ eff > 10 cm 2 /(V s)) channels comparable to vacuum-deposition. Sol–gels require high temperatures and 100–1000× longer times than CLMP to drive elimination and condensation reactions to completion.…”

Synthesis and Selenization of Thickness-Controllable In2O3 Films by Printed Oxide Skin of Liquid Metals

“…17 Liquid metals are a group of metals or alloys with low-melting points and high fluidity such as gallium, indium, and bismuth. 18 Liquid metal exhibits both metallic and nonmetallic properties, which have been widely used in nanorobots, 19 biomedical fields, 20 optoelectronic devices, 21 and wearable electronic devices. 22 At the same time, a film-growth technique based on the characteristics of liquid metals (surface self-limiting oxidation and surface layering) for the synthesis of metal oxides has been proposed.…”

“…Liquid metals are a group of metals or alloys with low-melting points and high fluidity such as gallium, indium, and bismuth . Liquid metal exhibits both metallic and nonmetallic properties, which have been widely used in nanorobots, biomedical fields, optoelectronic devices, and wearable electronic devices . At the same time, a film-growth technique based on the characteristics of liquid metals (surface self-limiting oxidation and surface layering) for the synthesis of metal oxides has been proposed. , The liquid metal oxidizes spontaneously under trace oxygen conditions at the metal–air interface. − The oxides on the surface could be easily exfoliated to various substrates because the van der Waals interactions between the oxides and the substrate exceed the weak adhesion between the oxidation and the liquid metals …”

Gas sensors based on the oxide skin of liquid indium

“…38,42 Exfoliation of oxides from the surface of low melting point liquid metals has extensively been explored for electronic and piezoelectric applications. 22,43–48 However, the use of 2D oxides derived from liquid metal for gas sensing has rarely been reported. 49–53…”