2‐nm‐Thick Indium Oxide Featuring High Mobility

Abstract

Thin film transistors (TFTs) are key components for the fabrication of electronic and optoelectronic devices, resulting in a push for the wider exploration of semiconducting materials and cost‐effective synthesis processes. In this report, a simple approach is proposed to achieve 2‐nm‐thick indium oxide nanosheets from liquid metal surfaces by employing a squeeze printing technique and thermal annealing at 250 °C in air. The resulting materials exhibit a high degree of transparency (>99 %) and an excellent electron mobility of ≈96 cm2 V−1 s−1, surpassing that of pristine printed 2D In2O3 and many other reported 2D semiconductors. UV‐detectors based on annealed 2D In2O3 also benefit from this process step, with the photoresponsivity reaching 5.2 × 104 and 9.4 × 103 A W−1 at the wavelengths of 285 and 365 nm, respectively. These values are an order of magnitude higher than for as‐synthesized 2D In2O3. Utilizing transmission electron microscopy with in situ annealing, it is demonstrated that the improvement in device performances is due to nanostructural changes within the oxide layers during annealing process. This work highlights a facile and ambient air compatible method for fabricating high‐quality semiconducting oxides, which will find application in emerging transparent electronics and optoelectronics.

Visible-Active Artificial Synapses Based on Ultrathin Indium Oxide

“…Hence, this study provides a pathway to utilize ultrathin In 2 O 3 layers as visible-active artificial optoelectronic synapses, which can find applications in next-generation bionic eyes and intelligent display systems. 28 ■ RESULTS AND DISCUSSION Atomically thin In 2 O 3 sheets are prepared using the LM synthesis technique followed by annealing (Figure 1a), to improve disorder at the grain boundaries of the material alongside increasing the grain size for improved mobility and photodetection properties 25 (see the Experimental Section for further details). Figure 1b shows the AFM characterization of a eV and the presence of oxygen peaks at 529.9 eV, which is in accordance with that of c-In 2 O 3 reported in the literature.…”

“…25 With increasing grain sizes due to annealing, there is a reduction in the intergranular distorted region in the polycrystalline sheet, resulting in improved mobility due to fewer barriers. 25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation.…”

“…25 This increased mobility also results in increased carrier diffusion length, which improves the charge carrier extraction within the system, resulting in increased photocurrent in the annealed samples in comparison to the pristine ones. 25 Furthermore, it has also been demonstrated previously that despite the generation of photocurrent in In 2 O 3 due to existence of V o , the presence of more than required V o in In 2 O 3 acts as recombination centers passivating photocurrent generation. 23 Such an excess number of V o can be passivated through annealing, which improves the overall photocurrent generation in In 2 O 3 and response to visible light.…”

“…The high-resolution TEM image of a polycrystalline grain indicates a d-plane spacing of 0.3 nm, which is associated with the (222) plane of cubic In 2 O 3 25. The ring-like selected area electron diffraction (SAED) patterns (as seen in Figure1d) further affirm the polycrystalline nature of the In 2 O 3 nanosheets, which can be associated with minimized anisotropic carrier mobilities along the material's crystal axis 25. The low-resolution TEM image and AFM and optical images of the nanosheet are shown in Supporting Information Section 1Figure S1.…”

Liquid Metal Interface for Two-Precursor Autogenous Deposition of Metal Telluride–Tellurium Networks

“…These properties make gallium-based alloys particularly suitable for a wide range of applications in flexible electronics and soft robotics alongside chemical and electrochemical processes. − In the context of electrochemistry, one of the most intriguing merits of liquid metals is the dynamic liquid–liquid interface that is established when they are in contact with an immiscible electrolyte . The liquid metal–electrolyte interface offers an atomically smooth yet electrochemically active template for growing or depositing a range of precursors into thin layers, , which presents great tunability for synthesizing materials in the nanoscale. , …”