Few-layer black phosphorous (BP) has emerged as a promising candidate for next-generation nanophotonic and nanoelectronic devices. However, rapid ambient degradation of mechanically exfoliated BP poses challenges in its practical deployment in scalable devices. To date, the strategies employed to protect BP have relied upon preventing its exposure to atmospheric conditions. Here, an approach that allows this sensitive material to remain stable without requiring its isolation from the ambient environment is reported. The method draws inspiration from the unique ability of biological systems to avoid photo-oxidative damage caused by reactive oxygen species. Since BP undergoes similar photo-oxidative degradation, imidazolium-based ionic liquids are employed as quenchers of these damaging species on the BP surface. This chemical sequestration strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics. This study opens opportunities to practically implement BP and other environmentally sensitive 2D materials for electronic applications.

Highly confined and low-loss polaritons are known to propagate isotropically over graphene and hexagonal boron nitride in the plane, leaving limited degrees of freedom in manipulating light at the nanoscale. The emerging family of biaxial van der Waals materials, such as α-MoO3 and V2O5, support exotic polariton propagation, as their auxiliary optical axis is in the plane. Here, exploiting this strong in-plane anisotropy, we report edge-tailored hyperbolic polaritons in patterned α-MoO3 nanocavities via real-space nanoimaging. We find that the angle between the edge orientation and the crystallographic direction significantly affects the optical response, and can serve as a key tuning parameter in tailoring the polaritonic patterns. By shaping α-MoO3 nanocavities with different geometries, we observe edge-oriented and steerable hyperbolic polaritons as well as forbidden zones where the polaritons detour. The lifetime and figure of merit of the hyperbolic polaritons can be regulated by the edge aspect ratio of nanocavity.

Non-volatile resistive memory devices are theorized to be the most promising pathway towards analog memory and neuromorphic computing. Two-dimensional MoO3 is a versatile planar transition metal oxide, whose properties can be readily tuned, making it anywhere from a wide bandgap semiconductor to a semi-metal. Successful integration of such a planar metal oxide into resistive memory can enable adaptive and low power memory applications. Here, we investigate the non-volatile and reversible resistive switching behaviour of oxygen deficient MoOx in a cross-point metal/insulator/metal (MIM) architecture. Layered MoOx films are synthesised using chemical vapour deposition (CVD) and reveal excellent resistive switching performance with relatively low electroforming and operating voltages. Switching ratios of ∼103 and stable data retention of >104 s are achieved. As such, this work demonstrates the viability of MoOx as a resistive memory element and paves the way for future two-dimensional resistive memory technologies.

The human skin is the largest sensory organ, made up of complex sensors that detect noxious stimuli to rapidly send warning signals to the central nervous system to initiate a motor response. It is complex to mimic key skin features using existing tactile sensors, and there exists no somatosensor that responds to real stimuli of pressure, temperature, and touch. Herein, three critical skin receptors created by realizing integrated electronic systems that mimic the feedback response of somatosensors are experimentally demonstrated. Fully functional Pacinian corpuscles, thermoreceptors, and nociceptors are realized using a combination of stretchable pressure sensors, phase‐change oxide thin films, and threshold‐based resistive switching (memristor) memory elements. The ability to detect and respond to pressure, temperature, and pain stimuli above a threshold with real‐life performance characteristics is demonstrated with explanation of underlying mechanisms. The ability to design and realize artificial skin receptors enables replacement of affected human skin regions, augment skin sensitivity for agile applications in defense and sports, and drive advancements in intelligent robotics.