Direct Determination of Band Gap of Defects in a Wide Band Gap Semiconductor

Resistance behavior of Sb7Se3 thin films based on flexible mica substrate

In this paper, we explored the resistivity behavior of Sb7Se3 thin films on flexible mica. The films maintained their resistance characteristics through various thicknesses and bending cycles. With increasing bends, resistivity and phase transition temperature of both amorphous and crystalline states rose, while the resistance drift coefficient gradually increased. Raman and near infrared experiments confirmed the internal structural changes and bandgap enhancement after bending. Transmission electron microscopy showed enhanced crystallization and uniform element distribution after annealing. Atomic force microscopy observed cracks, explaining the property changes. Additionally, we developed a flexible Sb7Se3 thin-film resistive device with swift reversibility (∼10 ns) regardless of bending, opening new avenues for flexible information storage.

Design Strategies for Perovskite-Type High-Entropy Oxides with Applications in Optics

It is essential and challenging to develop advanced ceramic materials with thermal stability and high reflectivity for optical fields. Encouragingly, recent breakthroughs and significant advances in high-entropy ceramics have made high-entropy oxides a potential candidate material for optical applications. Therefore, in this study, we analyzed the effect of lattice distortion on the design of high-reflectivity, high-entropy oxides using first-principles calculations and aberration-corrected microscopy. In order to optimize the optical properties of the materials, a series of novel perovskite-type high-entropy oxides, (LaxK0.4-xCa0.2Sr0.2Ba0.2)TiO3+δ (x = 0.1, 0.15, 0.2, 0.25, 0.3), were designed and synthesized using solid-state sintering based on the charge conservation principle and bond energy principle. When the content of La in the A-site element was 30%, the optical reflectivity reached 94% by suppressing the oxygen vacancy. Furthermore, we have successfully prepared a series of coatings by air spraying based on the regulation of the mass ratio of resin and powder. Compared to the uncoated substrate, the backside temperature can be reduced by 41%. This work provides a feasible design route with the first clear guidelines for highly reflective high-entropy ceramic materials and enables highly stable material design in multielement spaces.

Interfacial interaction and intense interfacial ultraviolet light emission at an incoherent interface

Incoherent interfaces with large mismatches usually exhibit very weak interfacial interactions so that they rarely generate intriguing interfacial properties. Here we demonstrate unexpected strong interfacial interactions at the incoherent AlN/Al₂O₃ (0001) interface with a large mismatch by combining transmission electron microscopy, first-principles calculations, and cathodoluminescence spectroscopy. It is revealed that strong interfacial interactions have significantly tailored the interfacial atomic structure and electronic properties. Misfit dislocation networks and stacking faults are formed at this interface, which is rarely observed at other incoherent interfaces. The band gap of the interface reduces significantly to ~ 3.9 eV due to the competition between the elongated Al-N and Al-O bonds across the interface. Thus this incoherent interface can generate a very strong interfacial ultraviolet light emission. Our findings suggest that incoherent interfaces can exhibit strong interfacial interactions and unique interfacial properties, thereby opening an avenue for the development of related heterojunction materials and devices.