Abstract Balancing carrier transport, electrostatic control, and operational stability remains a central challenge in oxide thin-film transistors (TFTs). Here, a 20 nm vertically compositiongraded ITO/ZnO channel was developed with a ZnO-rich region adjacent to the gate dielectric and a progressively increasing ITO fraction toward the source/drain contacts. The channel was fabricated by sequential RF magnetron sputtering followed by annealing at 350 • C. Cross-sectional TEM and EDS analyses revealed a continuous, compositionally intermixed oxide film retaining the intended depth-dependent Zn/In distribution, while XRD and XPS revealed a nanocrystalline metal-oxygen network containing defect-related oxygen states. The resulting TFTs exhibited near-zero-threshold enhancement-mode operation with a threshold voltage of 0.18 V, an I ON /I OFF ratio exceeding 10 6 , a hysteresis of 0.2 V, and a maximum effective field-effect mobility of 37.15 ± 0.28 cm 2 V -1 s -1 across five devices. After 3600 s of positive-and negative-bias stress, the threshold-voltage shifts were +0.43 and -1.25 V, respectively, while operation at 150 • C produced a shift of -0.40 V. The preserved on-state characteristics suggest that these shifts are predominantly associated with defect-mediated charge redistribution rather than substantial degradation of the conduction pathway. These results establish vertical composition grading as an effective strategy for combining high mobility, near-zero-threshold switching, and operational stability in sputtered oxide TFTs.
Abstract Controlling the spatial localization of electronic states is a fundamental strategy for manipulating charge and energy at the nanoscale. In coupled nanostructures, however, the localization field depends strongly on coupling between confinement regions, complicating comparisons across geometries. Here, we show that ground-state electric-field-induced localization follows a common master curve governed by a single dimensionless parameter comparing electrostatic detuning and quantum coupling. Using a one-dimensional effective-mass model for the stacking direction of a disorder-free five-layer GaAs/Al 0.3 Ga 0.7 As superlattice with L y = 10 nm, we vary only the interlayer barrier thickness, changing the zero-field coupling scale by more than two orders of magnitude. Despite widely different localization fields, charge-transfer and normalized Stark-shift curves nearly collapse when expressed in terms of Λ = eE ext d/W 1 (0). A five-site nearest-neighbor tight-binding model, with hopping fixed by the continuum zero-field manifold width, reproduces the master curve and predicts reduced thresholds within a few percent without additional fitted parameters. Small systematic departures occur in the strong-coupling regime at deep localization, where absolute fields produce intra-well deformation beyond a one-orbital description. These results establish, within this structural family, a simple connection between the zero-field electronic spectrum and the electric field required for nanoscale ground-state localization, providing a predictive framework for the design of field-tunable coupled quantum structures.
Abstract Emission control and enhancement of emitters are cornerstones of modern light-emitting, display, and optical sensing technologies. Over the past decades, research on stained nanoporous anodic alumina (NAA) platforms for optical and photonic applications has evolved from understanding the NAA structure–dye property correlations to the design of photoluminescent sensors. In particular, correlating optical properties with geometrical features of the NAA has become a major focus. Because NAA can effectively immobilise molecules smaller than its pores such as organic dyes, these nanoporous solid-state platforms could be used as light-emitting devices, dye-sensitised solar cells, protonation–deprotonation indicators, and photoluminescent sensors. They have also demonstrated potential for enhancing light-matter interactions through slowing light near the photonic bandgap, leading to narrowband laser action. In recent years, many scientific papers have been published on the concept, fabrication, and characterisation of stained NAA platforms with uniform and modulated nanopore diameters. This review highlights the transformative potential of stained NAA platforms, focusing on the critical role played by organic dyes, which act as gain media immobilised in the ordered nanostructures, in generating the desired emissions. It aims to trace the evolution of this field and provide an accessible overview for researchers working on or interested in stained NAA platforms. By synthesising previous advances, we provide a forward-looking perspective on the development of stained NAA platforms, proposing a greater focus on interactions dye–dye and dye–NAA interactions.
Abstract Liquid-metal-derived oxide nanofilms have emerged as promising candidates for scalable electronic materials, yet the oxidation pathway governing their electrical functionality remains poorly understood. Here, we report a systematic study on the thermally driven oxidation behavior of liquid-metal-printed gallium films and its decisive role in inducing a conductive-toinsulating transition for two-dimensional (2D) electronics. Ultrathin gallium-based films were prepared through a dewetting-enabled printing process under ambient conditions, yielding smooth and transferable films with single-layer thicknesses of ~4.5 nm. The as-printed films exhibit partial surface oxidation while retaining residual metallic gallium, resulting in conductive vertical transport. Pure oxygen exposure at room temperature leads mainly to surface adsorption of oxygen species and fails to achieve complete oxidation. In contrast, thermal annealing in oxygen-containing atmosphere progressively converts metallic Ga into gallium oxide, as evidenced by X-ray photoelectron spectroscopy. High-temperature treatment further induces crystallization into polycrystalline β-Ga 2 O 3 , confirmed by X-ray diffraction and Raman spectroscopy. Consequently, the printed films undergo a pronounced conductive-to-insulating transition, exhibiting pA-level leakage current, and a dielectric constant of ~4.2. When integrated as gate dielectrics in back-gated MoS 2 field-effect transistors, the devices deliver an on/off ratio of ~10 6 and a minimum subthreshold swing of 74 mV/dec. This work clarifies the thermal oxidation mechanism of liquid-metal-printed gallium films and establishes a scalable route toward functional dielectric layers for next-generation 2D electronics.
This corrigendum corrects the inset photographs of the centrifuge tubes in Figure 4a (1), Figure 4b (1), and Figure 4c (1), which were inadvertently mispresented during figure compilation. The appropriate images have now been provided. These corrections are limited to figure presentation and do not affect the original experimental data, results, interpretation, or conclusions of the paper.
