Thermally stable BiTe/WSe Van Der Waals contacts for pMOSFETs application.

Novel van der Waals (vdW) contacts formed by layered BiTe are found effective in improving the performance of WSe pMOSFETs. As compared with conventional transition metal-based Ni/Au S/D contacts, over 10 times on-state current improvement is achieved. vdW interface formation between BiTe and WSe is confirmed by X-ray diffraction analysis and scanning transmission electron microscope observation.

Phase-change behavior of RuSbTe thin film for photonic applications with amplitude-only modulation.

GeSbTe (GST), the most mature phase-change materials (PCM), functions as a recoding layer in nonvolatile memory and optical discs by contrasting the physical properties upon phase transition between amorphous and crystalline phases. However, GST faces challenges such as a large extinction coefficient (k) and low thermal stability of the amorphous phase. In this study, we introduce RuSbTe as a new PCM to address the GST concerns.

Discovery of a metastable van der Waals semiconductor polymorphic crystallization of an amorphous film.

Here we report on the growth of thin crystalline films of the metastable phase GeTe. Direct observation by transmission electron microscopy revealed a Te-Ge-Te stacking with van der Waals gaps. Moreover, electrical and optical measurements revealed the films exhibted semiconducting properties commensurate with electronics applications.

Tunable pheromone interactions among microswimmers.

Indirect interactions via shared memory deposited on the field ("field memory") play an essential role in collective motions. Some motile species, such as ants and bacteria, use attractive pheromones to complete many tasks. Mimicking these kinds of collective behavior at the laboratory scale, we present a pheromone-based autonomous agent system with tunable interactions.

Dimensional transformation of chemical bonding during crystallization in a layered chalcogenide material.

Two-dimensional (2D) van der Waals (vdW) materials possess a crystal structure in which a covalently-bonded few atomic-layer motif forms a single unit with individual motifs being weakly bound to each other by vdW forces. CrGeTe is known as a 2D vdW ferromagnetic insulator as well as a potential phase change material for non-volatile memory applications. Here, we provide evidence for a dimensional transformation in the chemical bonding from a randomly bonded three-dimensional (3D) disordered amorphous phase to a 2D bonded vdW crystalline phase.

Bidirectional Selector Utilizing Hybrid Diodes for PCRAM Applications.

Three-dimensional crossbar technology has been of great significance for realizing high density and multiple terabytes of data storage in memory devices. However, to further scale down the size of memory devices, a selector exhibiting nonlinear electrical properties should be in series with a memory layer in case of unwanted sneak current disturbance. Conventional selectors usually utilize a complicated multilayer structure to realize the high nonlinearity of current, which might be incompatible with certain manufacturing processes or limit the scalability of memory.

Cr-Triggered Local Structural Change in CrGeTe Phase Change Material.

CrGeTe (CrGT) is a phase change material with higher resistivity in the crystalline phase than in the amorphous phase. CrGT exhibits an ultralow operation energy for amorphization. In this study, the origin of the increased resistance in crystalline CrGT compared to amorphous CrGT and the underlying phase change mechanism were investigated in terms of both local structural change and associated change in electronic state.

Inverse Resistance Change CrGeTe-Based PCRAM Enabling Ultralow-Energy Amorphization.

Phase-change random access memory (PCRAM) has attracted much attention for next-generation nonvolatile memory that can replace flash memory and can be used for storage-class memory. Generally, PCRAM relies on the change in the electrical resistance of a phase-change material between high-resistance amorphous (reset) and low-resistance crystalline (set) states. Herein, we present an inverse resistance change PCRAM with CrGeTe (CrGT) that shows a high-resistance crystalline reset state and a low-resistance amorphous set state.