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Due to the limitation of inherent ultra-high electron concentration, the electrical properties of In2O3 resemble those of conductors rather than semiconductors prior to special treatment. In this study, the effect of various annealing treatments on the microstructure, optical properties, and oxygen vacancies of the films and transistors is systematically investigated. Our finding reveals a progressive crystallization trend in the films with increasing annealing temperature. In addition, a higher annealing temperature is also associated with the reduction in the concentration of oxygen vacancies, as well as an elevation in both optical transmittance and optical bandgap. Furthermore, with the implementation of annealing process, the devices gradually transform from no pronounced gate control to exhibit with excellent gate control and electrical performances. The atomic layer deposited Hf-doped In2O3 thin film transistor annealed at 250 °C exhibits optimal electrical properties, with a field-effect mobility of 18.65 cm2 V−1 s−1, a subthreshold swing of 0.18 V/dec, and an Ion/Ioff ratio of 2.76 × 106. The results indicate that the impact of varying annealing temperatures can be attributed to the modulation of oxygen vacancies within the films. This work serves as a complementary study for the existing post-treatment of oxide films and provides a reliable reference for utilization of the annealing process in practical applications. [ABSTRACT FROM AUTHOR]

The relocation of peripheral transistors from the front-end-of-line (FEOL) to the back-end-of-line (BEOL) in fabrication processes is of significant interest, as it allows for the introduction of novel functionality in the BEOL while providing additional die area in the FEOL. Oxide semiconductor-based transistors serve as attractive candidates for BEOL. Within these categories, In2O3 material is particularly notable; nonetheless, the excessive intrinsic carrier concentration poses a limitation on its broader applicability. Herein, the deposition of Hf-doped In2O3 (IHO) films via atomic layer deposition for the first time demonstrates an effective method for tuning the intrinsic carrier concentration, where the doping concentration plays a critical role in determine the properties of IHO films and all-oxide structure transistors with Au-free process. The all-oxide transistors with In2O3: HfO2 ratio of 10:1 exhibited optimal electrical properties, including high on-current with 249 µA, field-effect mobility of 13.4 cm2 V−1 s−1, and on/off ratio exceeding 106, and also achieved excellent stability under long time positive bias stress and negative bias stress. These findings suggest that this study not only introduces a straightforward and efficient approach to improve the properties of In2O3 material and transistors, but as well paves the way for development of all-oxide transistors and their integration into BEOL technology. [ABSTRACT FROM AUTHOR]

Constructing multiple nanosized heterogeneous structures with an in situ optimized coordination environment for dispersing and stabilizing noble metal single atoms (SAs) is a highly effective strategy for high-efficiency utilization of SAs and improving the electrocatalytic performances of the oxygen evolution reaction (OER). Herein, a multi-crystalline-amorphous heterogeneous composite (CoP2@CN–Ir(200)) composed of crystalline CoP2, amorphous CoOx and amorphous N-doped carbon was constructed for in situ loading of Ir SAs by cyclic voltammetry (CV) electrodeposition in an ionic liquid. By precisely controlling the electrodeposition cycles, the loading matrix of Ir SAs was simultaneously reconstructed and optimized. Some of the crystalline CoP2 is transformed into amorphous CoOx with activated high-valence Co; a coordination environment toward oxygenated species is built with more lattice oxygen and stronger adsorption ability of oxygen; the abundant heterointerfaces and the enhancement of the oxidation state disperse and stabilize Ir atoms in the form of OER-favorable high-valence Ir3+/Ir4+ by covalent Ir–O bonds (including Ir–O–Co bonds). As a result, abundant active sites with high intrinsic activity are exposed, and an accelerated charge transfer rate can be achieved, endowing CoP2@CN–Ir(200) with an outstanding electrocatalytic activity. Ultralow overpotentials of 189 and 300 mV at 10 and 100 mA cm−2, respectively, are achieved with a small Tafel slope of 36.9 mV dec−1, surpassing most reported remarkable Ir-related catalysts. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting provides a scalable and integrated platform to harness renewable solar energy for green hydrogen production. The practical implementation of PEC systems hinges on addressing three critical challenges: enhancing energy conversion efficiency, ensuring long-term stability, and achieving economic viability. Metal–insulator–semiconductor (MIS) heterojunction photoelectrodes have gained significant attention over the last decade for their ability to efficiently segregate photogenerated carriers and mitigate corrosion-induced semiconductor degradation. This review discusses the structural composition and interfacial intricacies of MIS photoelectrodes tailored for PEC water splitting. The application of MIS heterostructures across various semiconductor light-absorbing layers, including traditional photovoltaic-grade semiconductors, metal oxides, and emerging materials, is presented first. Subsequently, this review elucidates the reaction mechanisms and respective merits of vacuum and non-vacuum deposition techniques in the fabrication of the insulator layers. In the context of the metal layers, this review extends beyond the conventional scope, not only by introducing metal-based cocatalysts, but also by exploring the latest advancements in molecular and single-atom catalysts integrated within MIS photoelectrodes. Furthermore, a systematic summary of carrier transfer mechanisms and interface design principles of MIS photoelectrodes is presented, which are pivotal for optimizing energy band alignment and enhancing solar-to-chemical conversion efficiency within the PEC system. Finally, this review explores innovative derivative configurations of MIS photoelectrodes, including back-illuminated MIS photoelectrodes, inverted MIS photoelectrodes, tandem MIS photoelectrodes, and monolithically integrated wireless MIS photoelectrodes. These novel architectures address the limitations of traditional MIS structures by effectively coupling different functional modules, minimizing optical and ohmic losses, and mitigating recombination losses. [ABSTRACT FROM AUTHOR]

Titanium metal was successfully prepared from high-titanium slag via an electro-deoxidation process in molten CaCl2 melt in argon. The effects of sintering and electrolysis temperatures on the electro-deoxidation process were investigated. The results show that the porosity of the pellet decreases rapidly with the increase of sintering temperature, which reduces the available surface area between the pellet and the electrolyte, thus affecting the electro-deoxidation reaction. Electrolysis temperature affects the purity and particle size of the product. Excessive temperature causes the product re-sintering, which densifies the product particles and prevents the molten salt from entering the inside of the cathode, which is adverse to the electro-reduction of TiO2 to Ti. A moderate electrolysis temperature is more favorable for the electro-deoxidation reaction. Most of the impurities in the raw material move into the molten salt, and a few impurities attached to the product are removed by washing with hydrochloric acid solution. [ABSTRACT FROM AUTHOR]

The surface and interface chemistry are critical for controlling the properties of two‐dimensional transition metal carbides and nitrides (MXenes). Numerous efforts have been devoted to the functionalization of MXenes with small inorganic ligands; however, few etching methods have been reported on the direct bonding of organic groups to MXene surfaces. In this work, we demonstrated an efficient and rapid strategy for the direct synthesis of 2D Ti3C2Tx MXene nanosheets with organic terminal groups in an organic Lewis acid (trifluoromethanesulfonic acid) solvent, without introducing additional intercalations. The dissolution of aluminum and the subsequent in situ introduction of trifluoromethanesulfonic acid resulted in the extraction of Ti3C2Tx MXene (T=CF3SO3−) (denoted as CF3SO3H−Ti3C2Tx) flakes with sizes reaching 15 μm and high productivity (over 70 %) of monolayers or few layers. More importantly, the large CF3SO3H−Ti3C2Tx MXene nanosheets had high colloidal stability, making them promising as efficient electrocatalysts for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]